Organic Chemistry

Question 1

• Principles of Reactivity:
• Steric Hindrance
• -> Increases or decreases reactivity
• Induction
• -> Does reactivity increase or decrease with more EN groups?
• Conjugation
• ->What is it?
• -> Does it increase or decrease reactivity?
• Ring Strain
• -> Do smaller angles increase or decrease reactivity?
• Resonance
• -> What is the true form of a molecule?
• Resonance Form Principles
• ->Rule of Least Charges
• -> Octet Principle
• ->Stabilization of Negative Charges
• ->Principle of Hybridization
• ——-> Negative charges are more stable on what orbital character and positive charges are more stable on what character?
• Redox Agents: what will strong reducing agents react with? Which ones won’t they react with?
• -> Oxidizing Agents
• —-> What are strong oxidizing agents? Weak ones?
• ——-> What does Tollens reagent do?
• ——-> What do strong oxidizing agents do to alcohols? What about weak ones?
• -> Reducing Agents

Answer 1

• Steric Hindrance: Reactivity decreases because of protecting groups, such as acetals, which block off the reactive center.
• Induction: Reactivity increases with more electronegative groups because it changes the distribution of charge and the distribution of resonance forms.
• Conjugation: Reactivity decreases with alternating single and double/triple bonds due to stabilization of resonance forms.
• Ring Strain: Smaller bond angles in a ring increase torsional strain, therefore increasing reactivity.
• Resonance: Resonance forms are a way to understand electron densities on a molecule with π bonds (double or triple bonds) next to a p orbital or lone pair).
• -> The “true form” of a molecule is a weighted hybrid of the different resonance forms.

-Resonance Form Principles: A way to determine which resonance forms are more significant and stable. These are guided by principles below.

–>Rule of Least Charges: The fewer charged atoms in a resonance form, the more stable it is.

–> Octet Principle: Resonance forms with full octets are more stable. Oxygen and nitrogen should nearly always have a full octet.

–>Stabilization of Negative Charges: Stability of negative charges is the inverse of basicity. For example, as electronegativity increases across a row of the periodic table, basicity decreases and stability increases.

–>Principle of Hybridization: Negative charges are more stable on atoms with greater proportion of s- character (for example sp, 50% s character, is more stable than sp3, 25% s character). Positive charges are more stable on atoms with lower proportion of s- character.

• Oxidizing Agents: Strong oxidizing agents are Jones reagent, or metallic oxides like K2CrO7, KMnO4 which will oxidize alcohols “all the way” to carboxylic acids. Weak oxidizing agents like PCC will oxidize a primary alcohol “one step away” to an aldehyde. The mild oxidizing agent Tollens reagent will selectively oxidize aldehydes but not ketones or alcohols.
• Reducing Agents: The strongest reducing agents are hydrides like LiAlH4. The hydride NaBH4 is slightly weaker than LiAlH4. It will reduce aldehydes and ketones to alcohols but will not be able to reduce esters, carboxylic acids, amides.

Question 2

• Nomenclature:
• Hydrocarbons
• Alcohols
• Amines
• Aldehydes
• Ketones
• Carboxylic Acids
• Esters
• Amide

What to ketones and aldehydes get reduced to?

Answer 2

• Hydrocarbons: Contains only C and H, Use suffix -ane, -ene, or -yne, ie methane
• -> Alkane: single bonds
• -> Alkene: has a double bond
• -> Alkyne: has a triple bond
• Alcohols: -OH group, Use prefix hydroxy- or suffix -ol, ie methanol
• -> 1o, 2o, 3o depending on number of C attached to the C- OH group
• Amines: N with lone pair of e-, Use prefix amino- or suffix - amine, ie methenamine
• -> 1o, 2o, 3o depending on number of C attached to the Nitrogen
• Aldehydes: C=O group on terminal C, Use suffix -al, ie methanal
• Ketones: C=O on non-terminal C, Use suffix -one, ie methanone
• Carboxylic Acids: OH-C=O, Use suffix -oic acid, ie propanoic group acid
• -> Highest priority functional group

-Esters: OR`-C=O Combine R group plus group carboxylic acid names, ie ethyl propanoate

• Amide: NH-C=O Use suffix -amide, ie group methanamide
• -> Carboxylic acid derivative

**Aldehydes get reduced to primary alcohols and ketone get reduced to secondary alcohols!

Question 3

• Geometric isomers:
• ->Enantiomers
• ———-> Which properties are the same and which ones are different?
• ->Racemic mixture
• ->Meso compounds
• —–> What is special about this?
• ->Diastereomers
• ->Cis-trans isomerism
• ->Conformational isomer forms
• ->2n rule
• ->Cyclohexane bonds

Answer 3

• Enantiomers: Non-superimposable mirror images with the same physical properties except rotation of polarized light. Different configurations at EVERY stereocenter and therefore rotate polarized light opposite ways.
• Racemic mixture: An equal mixture of two enantiomers. Because of the opposite rotation of polarized light, this mixture will have no optical activity.
• Meso compounds; A type of stereoisomer which is superimposable on its mirror image. Because of this symmetry, it is achiral and not optically active.
• Diastereomers: Non-superimposable, not mirror images. Some but not all chiral centers are different. An epimer differs at exactly one stereocenter.
• Cis-trans isomerism: A type of diastereomer. Cis- = groups on the same side of the carbon chain Trans- = opposite sides. Exist on compounds with double bonds or rings.
• Conformational isomer forms: Conformational isomers are stereoisomers that can be interconverted through rotation around a bond
• 2n rule: The number of possible stereoisomers is 2n, where n is the number of chiral carbons (central carbons with 4 DIFFERENT surrounding groups).
• Cyclohexane bonds: Equatorial: Parallel to the cyclohexane ring. Axial: Perpendicular to the ring.

Question 4

• Fisher Projections
• ->Fischer Projection Manipulations
• —–> What does 90o rotation do? 180o rotation?
• ——> What does switching two substituents do?
• Isomer Configurations
• ->Relative configuration
• ->Absolute configuration
• ->E/Z geometric isomers
• What is the difference between relative and absolute configuration?

Answer 4

• Fisher Projections: Horizontal lines represent bonds coming out of the page (wedge) while vertical lines represent bonds going into the page (dash).
• Fischer Projection Manipulations: 90o rotation inverts the stereochemistry while 180o rotation maintains the stereochemistry. Switching two substitutents results in inversion of stereochemistry.
• Relative configuration: Denoted by the letters D/L. Molecules have the same relative configuration when one substituent is different but others are in the same position. Assigned with reference to a standard molecule like glyceraldehyde.
• Absolute configuration: Denoted by the letters R/S. Refers to each individual stereocenter within a compound (as opposed to relative configuration which refers to a whole compound).
• ->To determine the configuration, use the Cahn-Ingold- Prelog priority rules:
  1) Rank functional group priority based on highest atomic number.
  2) Reorient the molecules so that the group with lowest priority sits behind the page.
  3) Draw a circle from groups 1-2-3; a (R) stereocenter will be clockwise and (S) will be counterclockwise

-E/Z geometric isomers: Use the Cahn-Ingold-Prelog priority rules and assign priority based on highest atomic number. (E) alkenes will have the highest priority groups on different sides and (Z) will be on the same side Mnemonic: zame side

Question 5

• Types of isomers
• Stereoisomers vs constitutional isomers
• Configurational isomers vs conformers
• -> Enantiomers and diasteremers
• Tautomers

Answer 5

• Isomers have the same molecular formula but different physical properties
• Stereoisomers vs constitutional isomers: Stereoisomers have the same bonds between atoms whereas constitutional isomers have different connectivity.
• Configurational (aka geometric) isomers vs conformers: Conformers can convert forms without breaking bonds whereas configurational isomers cannot.
• ->Types of configurational isomers: Two types: enantiomers which are mirror images and diastereomers which are not

Tautomers: Tautomers are constitutional isomers that easily interconvert through movement of a H+ and double bond.
–> Common example: keto/enol forms of aldehydes and ketones.

Question 6

• Nucleotphilic Reaction Concepts:
• ->Nucleophiles
• ——–> What type of atoms don’t you want in a nucleophile?
• ->Electrophiles
• ->Good leaving groups
• ->Poor leaving groups
• SN1 reaction
• # steps
• Principle
• Rate law
• Limiting factor
• Preferred carbon
• Solvent
• Strength of nucleophile
• Stereochemistry of Products
• SN2 reaction
• # steps
• Principle
• Rate law
• Limiting factor
• Preferred carbon
• Solvent
• Strength of nucleophile
• Stereochemistry of Products

Answer 6

• Nucleophiles: Nucleophiles donate electrons and are Lewis bases. The best nucleophiles are usually strong bases, and higher electronegativity means worse nucleophilicity.
• Electrophiles: Electrophiles are usually positively charged or polarized. Carbonyl groups are common electrophiles.
• Good leaving groups: Leaving groups are the group that is removed in a nucleophilic substitution reaction. Weak bases make good leaving groups, especially halogen gases like Cl- and Br- since they avoid competing in a reverse reaction.
• Poor leaving groups: Stronger bases like OH- are poor leaving groups because they are not stable after leaving the molecule
• Sn1
• # steps: Two steps
• Principle: First, carbocation formed as LG leaves, THEN nucleophile attacks either side
• Rate law: Unimolecular: Rate = k [substrate]
• Limiting factor: Stability of carbocation
• Preferred carbon: Tertiary or secondary carbon
• Solvent: Polar protic (ie alcohols, acetate) - Protic is H attached to N, F, or O
• Strength of nucleophile: Weak (usually neutral)
• Stereochemistry of Products: Racemic mixture of retained/inverted
• Sn2
• # steps: One step
• Principle: “Backside attack” of nucleophile simultaneous with LG leaving
• Rate law: Bimolecular: Rate = k [substrate] [nucleophile]
• Limiting factor: Steric hindrance
• Preferred carbon: Primary carbon (less hindered)
• Solvent: Polar aprotic (ie DMSO or acetone)
• Strength of nucleophile: Strong (usually negatively charged)
• Stereochemistry of Products: Inverted

Question 7

• Phenols
• ->Nomenclature
• ->Differences from other alcohols
• ->Quinones
• ->Ubiquinone
• Alcohols
• ->Primary alcohol oxidation
• ->Nomenclature
• ->Secondary alcohol oxidation
• —->Leaving group conversion: what are alcohols converted to in order to make better leaving groups?
• ->Acetal / ketal conversions

Answer 7

-Phenols: -OH group(s) attached to a benzene ring

• Nomenclature: Named by the relative position of -OH groups. In order of closest to furthest, it goes ortho, meta, para.
• -> Mnemonic: the -OH groups like to ROMP around the benzene ring.
• Differences from other alcohols: Phenols are more acidic because the benzene ring helps stabilize negative charges.
• Quinones : Produced by oxidation of phenols (two oxidized phenols joined by a double bond).
• Ubiquinone: A type of quinone, also called coenzyme Q, that is biologically important because it accepts electrons in the ETC and is reduced to ubiquinol.
• Primary alcohol oxidation: Oxidized to aldehyde by PCC. Oxidized to carboxylic acids by stronger oxidizing agents (ie Jones reagent).
• —->Mild oxidizers like Tollen’s reagent will selectively oxidize aldehydes to -COOH but not ketones or alcohols
• Nomenclature: Named using -ol (if highest priority functional group) or otherwise hydroxy-
• ->Primary, secondary, or tertiary depending on how many other C are attached to the carbon with the -OH group.
• Secondary alcohol oxidation: Oxidized to ketone by any oxidizing agent.
• Leaving group conversion: Alcohols can be converted to sulfonates such as mesylate or tosylate which are very good leaving groups for nucleophilic substitution reactions.
• Acetal / ketal conversions: Alcohols protect aldehydes or ketones by reacting and converting them to acetal or ketal, respectively.

Question 8

• Carbonyls
• -> α-carbons
• -> Aldehydes
• -> Ketones
• -> Reactivity difference
• Aldehydes - reactions
• ->Formation
• ->Oxidation
• ->Reduction
• ->Reaction with alcohol
• Ketones - reactions
• ->Formation
• ->Oxidation
• ->Reduction
• ->Reaction with alcohol
• Carbonyls - reactions
• -> What do nucleophilic reactions of the following compounds result in:
• ——–>Aldehydes and ketones?
• ———>Carboxylic Acids?
• ->Imine reactions
• ——> How are imines formed?
• ->Imine tautomerization
• ———> What is the tautomer of an imine?

Answer 8

• Carbonyls: Carbonyl groups are a C=O double bond found in aldehydes, ketones, and carboxylic acids. They are good electrophiles due to partial positive charge on the C.
• α-carbons: Defined as the carbon next to the carbonyl group. α- hydrogens are the H attached to the α-carbon.
• Aldehydes: Contain a carbonyl C=O group and use the suffix -al Aldehydes are more reactive toward nucleophilic substitutions.
• Ketones: Contain a carbonyl C=O group and use the suffix -one Aldehydes have the carbonyl group on the terminal C vs ketones on the non-terminal C (connected to two alkyl chains).
• Reactivity Difference: Ketones are less reactive toward nucleophilic substitutions, due to steric hindrance and instability of alpha carbon.
• Aldehydes - reactions:
• Formation: Aldehydes are formed by oxidation of primary alcohols, specifically using a weak agent like PCC.
• Oxidation: Aldehydes get oxidized to carboxylic acids.
• Reduction: Aldehydes get reduced to primary alcohols by hydrides (ie LiAlH4).
• Reaction with alcohol: Aldehyde + one equivalent of alcohol = hemiacetal. Aldehyde + two equivalents of alcohol = acetal
• Ketones - reactions:
• Formation: Ketones are formed by oxidation of secondary alcohols.
• Oxidation: Ketones cannot be further oxidized.
• Reduction: Ketones get reduced to secondary alcohols by hydrides (ie LiAlH4), the same reagents used to reduce aldehydes.

-Reaction with alcohol: Ketone + one equivalent of alcohol = hemiketal.
Ketone + two equivalents of alcohol = ketal
–>Similar reaction to aldehydes.

• Carbonyls - reactions:
• Nucleophilic addition reactions: Aldehydes and ketones have poor leaving groups, nucleophilic attacks result in protonation forming alcohols. Carboxylic acids have good leaving groups, nucleophilic attacks result in reformation of compound.
• Imine reactions: Nitrogen + carbonyls = imines. This can be reversed by using water to hydrolyze the imine.
• Imine tautomerization: Imines can undergo a tautomerization reaction to form its tautomer–enamines
• *Note: Amine is a single bond -NH/-NH2
• Imine is R-C=NR’ / R-C=N-H
• Enamine is R-C=C-NR’ / R-C=C-NH

Question 9

• Aldols
• -> Aldol Condensation
• Aldol Addition
• Dehydration
• Retro-aldol reactions
• Keto/enol tautomerization
• Enolates
• Kinetic and thermodynamic enolates

–>3 steps to find aldol products

–>4 steps to find aldol reactants

Answer 9

• An aldol is a compound with both an aldehyde and an alcohol.
• ->Aldol condensation reactions are important reactions where an aldehyde/ketone acts as both an electrophile (keto form) and a nucleophile (enol form)
• —>Keto is when the non-carbon molecule has the double bond and enol is when the carbon has the double bond when switching with the Hydrogen.
• Aldol Addition: First step of aldol condensation: Nucleophile, an enol form aldehyde/ketone + electrophile, which is keto form aldehyde/ketone. Creates a C-C bond.
• Dehydration: Second step of aldol condensation is dehydration (loss of water), which creates an enone with a double bond
• Retro-aldol: Reverse aldol reaction. Cleavage of bond between alpha and beta carbon. Seen in glycolysis.
• Tautomerization: Aldehydes and ketones have keto and enol isomer forms. The enol form has the double bond and hydrogen switched. The keto form is more stable and common.
• Enolates: An anion formed by the removal of an α-hydrogen via reaction with a base from the enol form of aldehyde/ketone, stabilized by resonance. This form is more nucleophilic but less stable.
• Kinetic and thermodynamic enolates: Kinetic is favored at low temperatures with strong bases with faster reactions. Thermodynamic is favored at high temperatures with weak bases with slower, irreversible reactions.

3 Steps:

1) Label attacking C=O as 1, alpha carbon as 2, and attacked C=O as 3
- > 1 always retains C=O
- >2 (at high temp –> condensation –> pi bind between C2 and C3) and (at low temp –> OH at C3)
- >3 add remaining groups

4 steps:

1) Find C=O
2) Number 2 and 3 towards the OH or pi bond
3) Break bond between 2 and 3
4) Reform C=O on 3

Question 10

• Carboxylic Acid and Derivatives:
• -> Anhydrides
• —> Formation
• —> Nomenclature
• —> Nucleophilic Subsitution
• —> Reaction with Amines
• -> Esters
• —> Formation
• —> Nomenclature
• —> Nucleophilic Subsitution
• —> Reaction with Amines
• -> Carboxylic Acids:
• —> Nomenclature
• —> Formation
• —> Reduction
• -> Amides
• —> Nomenclature
• —> Formation
• —> Nucleophilic Substitution
• Carboxylic Acid Reactions
• -> Nucleophilic acyl subsititution
• -> Nucleophilic Subsititution Products
• -> Decarboxylation

Answer 10

Anhydrides:
-Formation: Products of condensation reactions between two carboxylic acids.

• Nomenclature: Named by sequencing the parent carboxylic acids alphabetically plus “anhydride”.
• ->Example: propanoic acid + ethanoic acid => ethanoic propanoic anhydride
• Nucleophilic Subsitution: Can undergo cleavage by a nucleophile with several possible products.
• ->Example: cleavage by H2O results in two carboxylic acids.

-Reaction with Amines: Anhydrides combine with amines to generate amides and carboxylic acids

Esters:
-Compounds derived from carboxylic acids, where the -OH group is replaced by a -OR group. R group is any alkyl group

• Formation: Products of the Fischer esterification reaction which takes place between carboxylic acids and alcohols.
• Nomenclature: Named with the suffix -oate. Cyclic esters are named lactones.
• Nucleophilic Subsitution: Refers to the ester hydrolysis of fat using a strong base.
• Reaction with Amines: Can be attacked by a nucleophilic alcohol to undergo transesterification (exchange of ester groups)
• Carboxylic Acid Reactions
• -Nucleophilic acyl subsititution: The carbonyl group carbon is electrophilic. In various substitution reactions, this carbon undergoes nucleophilic attack resulting in departure of a leaving group.
• Nucleophilic Subsititution Products:
• ->Carboxylic acid + ammonia = amide
• ->Carboxylic acid + alcohol = ester
• ->Carboxylic acid + carboxylic acid = anhydride

-Decarboxylation: Spontaneous loss of a carbon, catalyzed by heat. Releases CO2. Link to biochem: pyruvate decarboxylation is part of the link step between glycolysis and the Krebs cycle.

Carboxylic Acids:
-Nomenclature: Named with the suffix -oic acid

• Formation: Formed by oxidation of primary alcohols or aldehydes by a strong agent like KMnO4
• Reduction: Can be reduced by hydrides like LiAlH4 to form a primary alcohol.

Amides
-Compounds containing a NH-C=O group

• Formation: Products of a condensation reaction between carboxylic acid derivatives (with good leaving groups) and amines.
• ->For example, Cl-C=O plus -NH2 will form an amide
• Nomenclature: Given the suffix -amide. Cyclic amides are named lactams.
• Nucleophilic Subsitution: Can undergo a hydrolysis reaction to form carboxylic acid under conditions of high temperatures, high acidity/basicity.

Question 11

• Phosphates
• -> In acid-base reactions
• -> Phosphodiester binds
• —–> Formation
• Amino Acids
• -> Structure
• -> Properties
• -> Peptide Bonds
• —–> Formation
• -> Peptide Bind Cleavage
• Amino Acid Synthesis
• -> In vitro synthesis
• -> Strcker synthesis: 3 starting reactants
• -> Gabriel synthesis: Main reactant

Answer 11

-Phosphates: Phosphoric acid is H3PO4 and contains a phosphate group PO43-

–> In acid-base reactions: Phosphoric acid is a very good buffer in reactions due to three H, each with different pKa.

–> Phosphodiester bonds: Phosphodiester bonds link together nucleotides in DNA.

–> Formation: Phosphodiester bond formation is catalyzed by DNA ligase and releases a pyrophosphate product.

• Amino Acids
• -> Structure: Has an α-carbon attached to four other groups:
  1) amino group
  2) carboxyl group
  3) H atom
  4) R group

–> Properties: Amino acids are amphoteric, meaning can be either an acid or a base. At a certain pH range, they exist as dipolar ions called zwitterions

–> Peptide Bonds: Links between amino acids. They have partial double bond character due to resonance among the C, N, O. Rotation around the bond axis is restricted.

–> Formation: Peptide bonds are formed when the N-terminus of an amino acid performs a nucleophilic attack on the C- terminus of another amino acid.

–> Peptide Bind Cleavage: Peptide bonds are cleaved in a hydrolysis reaction, catalyzed by protease enzymes (ie trypsin).

• Amino Acid Synthesis
• -> In vitro synthesis: Two methods of synthesizing amino acids in vitro: Strecker and Gabriel synthesis
  1) Strecker synthesis: Generates amino acid from aldehyde
  2) Gabriel synthesis: Generates amino acid from potassium phthalimide

–> Strecker synthesis: Makes amino acids starting from aldehyde plus KCN and NH4Cl

–> Gabriel synthesis: Makes amino acids starting from potassium phthalimide. Potassium phthalimide acts as a nucleophile in a Sn2 reaction

Question 12

• Experimental Methods
• Seperation Methods:
• -> Extraction
• -> Wash
• -> Filtration: Liquid vs solid?
• -> Crystallization
• -> Chromatography
• Gel electrophoresis:
• -> Gel
• -> Southern Blot
• -> Northern Blot
• -> Western Blot
• Distillation Methods:
• -> Distillate
• -> Simple Distillation
• -> Fractional Distillation
• -> Vacuum Distillation
• Chromatography Methods:
• -> Paper
• -> TLC
• -> Gas
• -> HPLC
• -> Gel Filtration
• -> Ion Exchange
• -> Affinity
• cDNA cloning
• -> cDNA generation
• -> cDNA amplification
• -> cDNA cloning
• -> DNA libraries
• Other Experimental Techniques:
• -> ELISA
• -> Gene Knockout Models
• -> Tollens Test
• Sanger Seqeuncing
• -> Chain Termination
• -> Seperation

Answer 12

• Seperation Methods:
• Extraction: Extraction uses two layered fluids, one nonpolar and the other polar to dissolve a compound of interest. If the compound of interest is polar it will dissolve in the polar layer whereas if nonpolar it will dissolve in the nonpolar layer. Like dissolves like.
• Wash: Uses nonpolar and polar layers similar to extraction. Dissolves impurities outside of the compound of interest, whereas in extraction the compound of interest is dissolved.
• Filtration: Isolate a solid from a liquid (like a Brita filter). If interested in the solid, use vacuum filtration; if interested in liquid, use gravity filtration.
• Crystallization: Used to purify an impure compound. Heat to high temperature, then after cooling at a slow rate, the pure substance will crystallize first. This occurs because impure substances have lower freezing points than pure substances. Generally will not result in a 100% pure compound.
• Chromatography: Used to separate a mixture based on speed of movement through a medium. The mixture is dissolved in a mobile phase fluid, usually liquid and nonpolar. Then passes through a stationary phase structure, usually solid and polar.
• Gel electrophoresis:
• Gel: Agarose gel is used for larger molecules like nucleic acids. Polyacrylamide gel has smaller pores for proteins.
• Southern Blot: Used to detect a target sequence of DNA. A sample is run through gel electrophoresis before adding a fluorescent probe made of single stranded DNA complementary to the target sequence.
• Northern Blot: Similar to Southern blot but used to detect RNA.
• Western Blot: Used to detect level of a target protein. Sample is separated through electrophoresis and then a fluorescent antibody specific to the protein is added. The intensity of the electrophoresis band corresponds with the concentration of the target. A control protein, which has stable expression under different conditions, is used as a reference.
• Distillation Methods: Separates two liquids according to their boiling points. Heating too rapidly may cause poor separation.
• Distillate: Refers to the liquid with the lower boiling point.
• Simple Distillation: Used for liquids with large differences in boiling point but generally will not result in a pure compound.
• Fractional Distillation: Uses a column of glass beads to essentially cause repeated distillations. Compared to simple distillation, allows for purification of compounds with small differences in boiling points (<25oC).
• Vacuum Distillation: Uses a low pressure environment in order to lower the boiling point of all liquids. This allows separation of liquids at lower temperatures, since some substances decompose at temperatures >150 oC
• Chromatography Methods:
• Paper: Separation mechanism - Affinity for paper –> Used to separate pigments in a dye.
• TLC: Separation mechanism - Polarity –> Stationary phase is polar so nonpolar substances move faster and further.
• –>Retention factor = (distanced moved by solute) / (distance moved by solvent).
• Gas: Separation mechanism - Boiling Point –> Mobile phase is an inert gas while stationary phase is a liquid
• HPLC: Separation mechanism - Polarity –> Normal phase = nonpolar mobile phase, polar stationary phase; Reverse phase = polar mobile phase, nonpolar stationary phase
• Gel Filtration: Separation mechanism - Size –> Uses pores that slow down smaller molecules
• Ion Exchange: Separation mechanism - Ionic charge –> Column filled with charged beads. Cation beads repel positively charged molecules to elute first and vice versa.
• Affinity: Separation mechanism - Binding affinity to chosen ligand –> Molecules with high ligand affinity will get stuck on beads and move slower. Examples of ligands would be nickel or antibodies.
• cDNA cloning: Purpose is to clone a sequence of cDNA (“copy DNA”) that codes for a specific protein, starting with a target mRNA sequence.
• cDNA generation: Starting with mRNA, reverse transcriptase is used to generate single- stranded cDNA
• cDNA amplification: The enzyme DNA polymerase is added with nucleotides to create and amplify double-stranded cDNA
• cDNA cloning: The cDNA and a plasmid vector are cut using restriction enzymes, then joined using DNA ligase. This vector can then be put into cells.
• DNA libraries: Two types of DNA libraries: genomic DNA libraries contain the whole transcript (including introns) while cDNA libraries contain specific genes, since they are made starting from mRNA.
• Other Experimental Techniques:
• ELISA: Uses an antibody to visually quantify the presence and concentration of a target protein.
• Gene Knockout Models: Uses gene targeting to downregulate (“knockout” model) a gene in a mouse. Used to determine impact on protein expression or function of a particular gene.
• Tollens Test: Used to test for reducing sugars such as aldehydes. Uses a silver oxidizing agent that reacts with free anomeric carbons. Can distinguish between aldehydes and non-reducing ketones Benedict’s and Fehling tests can also be used to test for reducing sugars.
• Sanger Seqeuncing: Used to determine the sequence of DNA
• Chain Termination: Uses dideoxynucleotides (ddNTP), which are like nucleotides but missing 3’ -OH, to terminate chains. In a large sample this results in different length strands that terminate at all possible positions of the DNA.

-Seperation: Electrophoresis is then used to separate the strands based on length and determine sequence.

Question 13

• Nuclear magnetic resonance principles:
• -> Peaks
• -> Calibration
• -> Shielding
• -> Splitting
• -> Electron Groups
• Infared Spectroscopy Peaks: Range and Peak Shape
• C=O
• C=C
• C≡C or C≡N
• N-H
• O-H

-Nuclear Magnetic Resonance Peaks:
Group:
-Hydrogens of sp3 carbons
-Hydrogens of sp2 carbons 
-Hydrogens of sp carbons 
-Hydrogens of aromatics 
-Aldehyde hydrogens
-Carboxylic acid hydrogens
-OH group hydrogens

Answer 13

• Nuclear magnetic resonance principles:
• Peaks: Each peak on NMR spectroscopy represents hydrogens that are chemically equivalent
• Calibration: NMR usually calibrated by a compound called TMS whose shift is at 0 ppm
• Shielding: Shielding decreases with electron-withdrawing groups due to increasing influence of the magnetic field
• Splitting: Also called spin-spin coupling. Adjacent hydrogens cause magnetic interference resulting in splitting of peaks on NMR spec.
• —-> # of peaks = (# of neighboring H within 3 bonds) + 1

-Electron Groups: Electron-donating groups increase shielding and are located more upfield (right). Electron-withdrawing groups decrease shielding and are located more downfield (left).

• -Infared Spectroscopy Peaks: Range and Peak Shape
• C=O : 1750 and Sharp
• C=C : 1600-1680 and Weak
• C≡C or C≡N : 1900 - 2200 and Medium
• N-H : 3300 and Sharp
• O-H : 3000 - 3300 and Broad
• Hydrogens of sp3 carbons: 0 to 3
• Hydrogens of sp2 carbons: 4.6 to 6
• Hydrogens of sp carbons: 2 to 3
• Hydrogens of aromatics: 6 to 8
• Aldehyde hydrogens: 8 to 10
• Carboxylic acid hydrogens: 10 to 12
• -OH group hydrogens: 1 to 5

Question 14

• Mass spectroscopy peaks
• ->Molecular ion peak
• ->Base peak
• ->M+1 peak
• ->M+2 peak
• ->m/z ratio
• Spectroscopy types:
• Infrared spectroscopy
• Ultraviolet spectroscopy
• Mass spectrometry
• Nuclear magnetic resonance spectroscopy

Answer 14

• Mass spectroscopy peaks:
• Molecular ion peak: Represents the molecule of interest
• Base peak: The tallest peak and represents the most abundant ion
• M+1 peak: A smaller peak to the right of the molecular ion peak. Represents the abundance of carbon
• M+2 peak: Represents the abundance of Br or Cl
• m/z ratio: The x-axis represents the m/z ratio, or the ratio of mass to charge. Signal intensity represents the quantity of particles at a given m/z ratio.
• Spectroscopy types:
• Infrared spectroscopy: Based on absorption of infrared light and the principle that vibration or rotation of bonds causes a net change in dipole moment. Useful for determining functional groups.
• Ultraviolet spectroscopy: Based on absorption of UV light, comparing absorption of a compound in a solvent with the reference as the solvent alone. Most useful for conjugated π-bond systems.
• Mass spectrometry: Mass spectrometry is based on electron collisions that result in ionization of compounds. Used for determining molecular structure or weight of a compound.
• Nuclear magnetic resonance spectroscopy: Measures nuclear spin using a magnetic field. Used for determining the functional groups of a compound.

Question 15

• Heisenberg Uncertainty Principle
• Pauli exclusion principle
• Hund’s rule
• Aufbau principle
• Diamagnetic vs paramagnetic
• Orbitals per shell and electrons per shell

Symbols:
n, l, ml, ms

Answer 15

-Heisenberg Uncertainty Principle: The position and momentum of an electron cannot be known simultaneously.

-Pauli exclusion principle: No two electrons can have the same four quantum numbers. Therefore:
paired electrons must have opposite spin (one +1/2, other -1/2)

-Hund’s rule: All orbitals in a subshell must contain at least one electron before any orbital can be filled with a second electron. The first electron in each orbital all have the same parallel spin, while the second electron in the orbital has opposite spin

-Aufbau principle: Electrons will fill the lower energy orbitals before moving to the higher energy orbitals.
Order in which energy of orbitals increases is determined by the (n+l) rule, where the sum of the principal (n) and azimuthal (l) quantum numbers determine the energy level of the orbital.

-Diamagnetic vs paramagnetic:
Diamagnetic: If there are no unpaired electrons. Results in being repelled by a magnetic field.
Paramagnetic: If there are any unpaired electrons. Results in being attracted by a magnetic field.

There are n2 orbitals per shell and therefore 2n2 electrons per shell

• n: Electron shell number.
• l: Subshell (3d shape) of orbital. 0 = s, 1 = p, 2 = d, 3 = f
• ml: Orbital subtype and orientation
• ms: Electron spin

Question 16

Chem Equations:

• Avogadro’s number
• Speed of light in a vacuum
• Planck’s constant (h)
• Energy of a photon
• Solubility constant
• Osmotic pressure
• Boiling Point Elevation
• Freezing Point Depression
• Vapor Pressure Lowering (Raoult’s law)
• Enthalpy
• Heat
• Gibbs free energy
• Gibbs free energy in redox under standard conditions
• Spontaneity by Gibbs free energy
• Henderson-Hasslebach
• Acid dissociation constant
• Base dissociation constant
• pH vs pOH
• Cell Potential - electromotive force
• Nernst equation
• —> When is it used
• Gibbs free energy in cells

Answer 16

• Avogadro’s number 6.022 x 1023. Number of atoms in a mol.
• Speed of light in a vacuum: 3.00 x 10^8 m/s
• Planck’s constant (h): 6.626 x 10-34 kg*m2/s
• Energy of a photon: E = hf = hc/λ
• -> f = frequency. h = Planck’s constant. c = speed of light. λ = wavelength.

-Solubility constant: Use the equilibrium expression. For example, for Ag2SO4:
Equilibrium expression:
Ag2SO4 ⟷ 2Ag+ + SO2- 4 –> Ksp = [Ag+]2[SO2-]

-Osmotic pressure = iMRT
i = van’t Hoff factor, M = molarity (mol/L), R = gas constant, T = temperature in Kelvin

-Boiling Point Elevation: ΔTb = iKbCm
i = ionization factor, Kb = elevation constant, Cm = concentration in molality

-Freezing Point DepressionL ΔTf = iKf Cm
i = ionization factor, Kf = depression constant, Cm = concentration in molality

-Vapor Pressure Lowering (Raoult’s law): Ptotal = Xsolvent * Psolvent
P = vapor pressure, X = mol fraction
–>Addition of a solute to a solvent will decrease its vapor pressure, since the mol fraction decreases

-Enthaply: -Enthalpy: ΔHreaction = ΔHproducts − ΔHreactants

• Heat (q): q = mcΔT
• -> m = mass, C = specific heat capacity, ΔT = change in temperature
• ——->Energy transferred due to a difference in temperature. Unit is Joules.

-Gibbs free energy: ΔG = ΔH − T ΔS
G = Gibbs free energy, H = enthalpy, T = temperature in Kelvin, S = entropy

• Gibbs free energy under standard redox: ΔG = −RT ln (Keq)
• -> R = gas constant, 8.31, T = temperature in Kelvin, Keq = equilibrium constant

-Spontaneity by Gibbs free energy: Gibbs free energy gives the spontaneity reaction of a reaction
Spontaneous if ∆G < 0
Equilibrium if ∆G = 0
Non-spontaneous if ∆G > 0

-Henderson-Hasselbach equation: pH = pKa + log ( [A−] ) / [HA] )
In other words: pH = pKa + log ( conjugate base / acid )

• Acid dissociation constant: Ka = ( [H+] [A−] ) / [HA]
• Base dissociation constant: Kb = ([OH−][B+]) / [BOH]
• pH vs pOH: pH = -log[H+]
• pOH = -log[OH-]
• pH = 14 - pOH
• Cell Potential : Eo cell = Eo cathode − Eo anode
• -> Ecell = 0 when Keq = 1
• Nernst Equation : Ecell = Eo cell − 0.0592 / n * log(Q)
• -> Eocell = standard cell potential, n = moles of electrons, Q = reaction quotient
• -> Used to calculate cell potential under non-standard conditions

ΔG = −nF Eo cell
n = moles of electrons, F = Faraday's constant (96485 C/mol)

Question 17

-Name Reactivity and trend down a group:
Alkali Metals
Alkaline Earth Metals
Transition Metals
Halogens 
Noble Gases

• Periodic Table Trends:
• Zeff
• Ionization energy
• Electron affinity
• Electronegativity
• Atomic radii

Answer 17

• Alkali metals 1 –> Very reactive –> Increases down a group - Forms hydroxides with wate
• Alkaline earth 2 metals –> Moderately reactive –> Increases down a group - Forms hydroxides with water
• Transition metals 3-12 –> Varies, but high conductivity
• Halogens 17 –> Very reactive –> Decreases down a group - Forms salts with group 1/2 metals
• Noble gases 18 –> Not reactive
• Periodic Table Trends:
• Zeff: The positive charge of protons on valence electrons
• -> Trend across a period: ↑ due to adding positive charge by adding a proton
• -> Trend down a group: ↓ due to e- shielding effect
• Ionization energy: Energy needed to remove e-, aka how hard it is to lose e-
• –> Trend across a period: ↑ due to increase in valence e- getting further from empty valence
• -> Trend down a group:↓ due to increasing radii
• Electron affinity: Energy released when add e-, aka how easy it is to gain e-
• –> Trend across a period: ↑ due to increase in valence e- getting closer to full valence
• -> Trend down a group:↓ due to increasing radii
• Electronegativity: The force an atom exerts on an electron in a bond
• –> Trend across a period:↑, remember that F is the most electronegative element
• -> Trend down a group:↓, remember that F is the most electronegative element
• Atomic radii: The radius of the atom
• –> Trend across a period:↓ due to increasing nuclear charge but ↑ when you jump a shell
• -> Trend down a group: ↑ due to adding shells

Question 18

• Bond Order
• Coordinate covalent bond
• Normality
• Solubility Rules
• Solubility rule exceptions
• -> Sulfate Exceptions
• -> Group 17 Exceptions

-Colligative Properties

Answer 18

• Bond Order: Bond order refers to the number of covalent bonds (ie single, double). Increasing bond order means increased bond strength and energy and decreased bond length.
• Coordinate covalent bond: Covalent bond formed when one atom provides both bonding electrons. Generally formed by Lewis acid-base interactions.
• Normality: Number of equivalents (ie number of H+ molecules for an acid) in 1 L of solution. Calculated by N = M (mol/L) x n (equivalents / mol).

-Solubility rules: NAG SAG is soluble.
N = nitrates (NO3-), A = acetates (C2H3O2-), G = Group 1 (Li+, Na+, etc), S = sulfates (SO42-), A = ammonium (NH4+), G = group 17 (F-, Cl- etc).
Sulfates and Group 17 have exceptions.

-Solubility rule exceptions:
Sulfate exceptions: PMS = Pb2+, Mercury, Silver and CASTRO BEAR = Ca2+, Strontium, and Barium.
Group 17 exceptions: PMS

–Colligative Properties: depends on the amount of substance, not type of substance

Question 19

• Ions
• -> Complex ion
• -> Chelate
• -> Common ion effect
• -> Nomenclature
• –> Hydrogen plus oxyanions
• —> Metal Cations
• Reactions
• Equilibrium Constant
• Reaction Quotient
• Kinetic Control vs Thermodynamic Control
• Rate Law
• Rate Constant
• Triple Point vs Critical Point

Answer 19

• Complex ion: A central metal ion (like Fe) is bound to ligands by coordinate covalent bonds.
• Chelate: Within a complex ion, when the same single ligand has multiple bonds to the central metal cation.
• Common ion effect: Application of Le Chatelier’s principle to solubility reactions. When you add ions, it shifts the equilibrium and therefore decreases solubility.
• Nomenclature:
• > Hydrogen plus oxyanions: Add hydrogen before the name. For example HCO3- = hydrogen carbonate.
• > Metal Cations: -ous for lesser charge and -ic for greater charge

-Equilibrium Constant: For an equation aA + bB ⇄ cC + dD: Keq = [C]c[D]d / [A]a[B]b. This equation is also called the law of mass action. Exclude pure solids and liquids as they are constant.

-Reaction Quotient: Describes a system not at equilibrium. Uses the same equation as Keq but the quantities are given at a single point in time rather than at equilibrium. Q = Keq at equilibrium
.
-Kinetic Control vs Thermodynamic Control:
–>Thermodynamic: Done at higher temperatures, promotes the more stable product.
–>Kinetic: Faster products, higher in free energy, but less stable product.

-Rate Law: For a single step reaction with equation A + B → C + D, the rate law will take the form of rate = k [A]a [B]b
The exponents can be determined experimentally. For example, when comparing two reaction results, if [A] doubles but the rate quadruples, then we know that the exponent a is 2

-Rate Constant: Rate constant must be determined empirically, ie through experimentation

• Triple Point vs Critical Point: The reaction order is the sum of all exponents in the rate law equation
• > Example: For rate = k [Mg]*[Cl]^2, this equation follows 1 + 2 = 3rd order kinetics

Question 20

• Thermochemistry
• -> State Functions vs Path Functions
• Enthalpy
• Open systems
• Closed systems
• Isolated systems
• Adiabatic process

Answer 20

-State Functions vs Path Functions: Independent of how current state was reached. Examples: Gibbs free energy, entropy. Contrast with path functions, which depend on how a state was reached. Examples: heat, work

• Enthalpy: ΔHreaction = ΔHproducts − ΔHreactants
• ->A measure of potential energy found in bonds. Equal to heat under conditions of constant pressure.
• Open systems: Exchange both matter and energy with environment.
• Closed systems: Exchange energy but not matter with environment.
• Isolated systems: Exchange neither matter nor energy with environment.
• Adiabatic process: Exchange no heat with the environment.

Question 21

• Acid-Base Chemistry
• > Arrhenius acid vs base
• > Brønsted-Lowry acid vs base
• > Lewis acid vs base
• > Amphoteric species Polyprotic acid
• > Equivalence point
• > Indicators
• > Litmus paper
• > Half-equivalence point
• > Conjugate pairs
• Electrochemistry
• Spontaneous vs non-spontaneous, cell potential, delta G, anode/cathode
• ->Galvanic (aka voltaic)
• ->Electrolytic
• ->Concentration
• -> Anode and cathode
• -> Flow

Answer 21

• Arrhenius acid vs base: Arrhenius acid: produces H+. Arrhenius base: produces OH-.
• Brønsted-Lowry acid vs base: Brønsted-Lowry acid: donates H+ ion. Brønsted- Lowry base: accepts H+ ion.
• Lewis acid vs base: Lewis acid: accepts electron pair. Lewis base: donates electron pair.
• Amphoteric species: Can act as either acid or a base.
• Polyprotic acid: Acid with multiple H+ ions. –> Note that Ka1 > Ka2 > Ka3
• —-> Each ionization step becomes more difficult. As the compound becomes more negatively charged, it becomes harder to remove H+

-Equivalence point: The point at which the equal amounts of acid and base have undergone the reaction. Also called endpoint.

-Indicators: Weak acid/bases that change color when going from protonated to unprotonated form. Important to choose an indicator whose pKa is close to the pH of the titration equivalence point so that it changes color in the appropriate range.
Note that indicators do not change the pH or buffering capacities of a solution, due to being added in miniscule amounts

-Litmus paper : Indicator that turns red in presence of a Brønsted-Lowry acid (H+ donor) and blue in presence of a Brønsted-Lowry base (H+ acceptor)

• Half-equivalence point: The point at which the concentration of acid equals the concentration of conjugate base. Also called the midpoint of the reaction.
• -> [HA] = [A-]
• -> pH = pKa

-Conjugate pairs: Strong acids have very weak conjugate bases and strong bases have very weak conjugate acids. Note that the inverse is not always true; weak acids do not always have strong conjugate bases and weak bases do not always have strong conjugate acids. The stability of the conjugate pair is a main factor in determining strength.

• Electrochemistry:
• Galvanic (aka voltaic) –> Spontaneous reactions
• -> Cell potential : +
• -> ∆G = -
• -> Anode (-), Cathode (+)
• ->Electrolytic –> Non-spontaneous reactions
• -> Cell potential : -
• -> ∆G = +
• -> Anode (+), Cathode (-)
• ->Concentration –> Spontaneous reactions
• -> Cell potential : 0
• -> ∆G = 0
• -> Both electrodes same material. Movement driven by concentration gradient
• Anode: site of oxidation, will attract anions.
• Cathode: site of reduction, will attract cations

-Flow: Electrons flow from anode to cathode for both galvanic and electrolytic cells

Question 22

Physics Equations:

• Kinetic energy of a gas
• Graham’s law
• Root mean square speed
• Dalton’s law
• Henry’s Law of Solubility
• Fick’s law of diffusion
• Ideal gas law equation
• Boyle’s law
• Charles’s law
• Gay-Lussac law
• Cross Product
• Dot Product
• Torque (rotational force)
• Friction
• Friction on an inclined plane
• Four kinematics equations
• Projectile motion
• Circular motion
• Hooke’s law
• Potential energy of spring

Answer 22

• Kinetic energy of a gas: KE = 3 KT^2
• -> KE = kinetic energy, K = Boltzmann constant, T = temperature Kinetic energy is directly proportional to temperature.
• Graham’s law: v1 / v2 = sq root (M2 / M1)
• -> Rate of gas effusion is inversely proportional to the square root of mass –> Lower molar mass results in faster effusion.
• Root mean square speed: V = sq root (3RT / M)
• -> Velocity is proportional to the square root of temperature.
• –> R = 8.3145 J/K*mol

-Dalton’s law:: Pi = PT Xi
–> X = mol fraction of the gas i, PT = total pressure
–> Total pressure = sum of partial pressures
.
-Henry’s Law of Solubility: Sgas = KHPgas
Sgas = Solubility of gas, KH = Henry’s Constant, Pgas = Partial Pressure
—->Amount of dissolved gas in a liquid is proportional to the partial pressure of the gas over the liquid.

-Fick’s law of diffusion: ΔV = (A⋅Dgas⋅ΔP) / T
–> ΔV = flow rate, A = area of membrane, T = thickness of membrane, ΔP = change in pressure, Dgas = diffusion constant
Describes diffusion of gas across a membrane

Ideal gas law equation: P V = nRT
P = pressure, V = volume, n = # of moles, R = gas constant, T = temperature

• Boyle’s law: P1V1 = P2V2 –> PV is constant
• Charles’s law: V1 / T1 = V2 / T2 –> V / T is constant
• Gay-Lussac law: P1 / T1 = P2 / T2 –> P / T is constant
• Cross Product: A x B = |A| |B| sin (θ) –> Results in a vector.
• Dot Product: A · B = |A| |B| cos (θ) –> Results in a scalar.
• Torque (rotational force): τ = rF sin(θ)
• -> τ = torque, r = radius, F = force, θ = angle between force and lever arm
• Friction: F = μFnormal
• -> μ = friction coefficient, m = mass, g = gravity constant, θ = angle of inclined plane.
• —–> Friction defined as force that opposes motion along a surface due to electrostatic interactions
• Friction on an inclined plane: F = μmg cos(θ)
• –> μ = friction coefficient, m = mass, g = gravity constant, θ = angle of inclined plane
• Four kinematics equations:
  1) v = v0 + at –> Velocity as a function of initial velocity, acceleration, and time
  2) v^2 = v0^2 + 2aΔ x –> Velocity as a function of initial velocity, acceleration, change in distance
  3) Δx = v0t + 1/2at^2 –> Displacement as a function of initial velocity, acceleration, time
  4) Δx = ((v+v0)/2)t –> Displacement as a function of initial velocity, velocity, time
• Projectile motion: v0 = sq rt (2gh)
• -> Use to find peak height. In projectile motion, horizontal velocity is constant and vertical velocity is determined by gravity.
• Circular motion:
• Centripetal acceleration = v^2 / r
• Centripetal force = mv^2 / r
• Hooke’s law: F = −kx
• –> F = force restoring spring to equilibrium, k = spring constant (stiffer = higher constant), x = displacement

-Potential energy of spring: U = 1/2 kx^2
U = elastic potential energy, k = spring constant, x = displacement length

-

Question 23

Physics Equations Part Two:

• Kinetic energy
• Elastic potential energy (for a spring)
• Gravitational potential energy
• Work Formula
• Work as a sum of energy
• Power (2 equations)
• Mechanical advantage
• Mechanical advantage of inclined plane
• Work of a gas
• 1st Law of Thermodynamics (normal and for a gas)
• Thermal expansion
• Heat
• Heat of phase change
• Planck’s Equation
• Diffraction grating
• Refraction
• Snell’s law
• Thin Lens Equation
• Focal length
• Magnification
• Optical power

Answer 23

• Kinetic energy: KE = 1/2 mv^2
• ——-> m = mass, v = velocity
• Elastic potential energy (for a spring): U = 1/2 kx^2
• —–> U = elastic potential energy, k = spring constant, x = displacement length
• Gravitational potential energy: U = mgh
• ——> U = potential energy, m = mass, g = gravity, h = height

-Work Formula: F ⋅ d = ∣F ∣∣D∣ cos(θ) –> Dot product of force and displacement

• Work as a sum of energy: W ork = ΔK + ΔU
• —> Sum of kinetic and potential energy changes

-Power: Rate of work over time. Unit: Watt (J/s)
Power =W/t =Fv –> W = work, t = time, F = force, v = velocity

• Mechanical advantage: MA = work accomplished / effort
• —-> A machine multiplies input force by the mechanical advantage factor to accomplish work.
• Mechanical advantage of inclined plane: MA = incline length / height
• —> The length of incline is the hypotenuse
• Work of a gas: W = −P ΔV
• —–> W = work, P = pressure, ΔV = change in volume
• 1st Law of Thermodynamics: ΔE = Q + W
• —> ∆E = change in energy of a system, Q = heat (negative if heat flows out of system, positive if heat flows in), W = work (negative if work is done by system, positive if work is done on system)
• For a gas, W = -P∆V, P = pressure, ∆V = volume
• Thermal expansion: ΔL = αLΔT
• -> Degree of expansion directly proportional to initial length (L) and change in temperature (T).
• Heat: q = mcΔT
• —> q = heat, m = mass, c = specific heat, T = temperature
• Heat of phase change: q = mL
• —–> q = heat, m = mass, L = heat of transformation
• Planck’s Equation: ΔE = hf
• -> h = Planck’s constant = 6.626 x 10-34 J s
• —-> Used to find the energy of a photon of light, which corresponds with the change in energy of electron orbital levels
• *Energy and wavelength are inverse of each other**

-Diffraction grating: An experimental setup with a series of slits that diffract light into its component colors.
d sin(θ) = mλ
--> θ = angle of separation, d = distance between slits, λ = wavelength, m = position of slit

• Refraction: n = c / v
• -> n = index, c = speed of light in vacuum, v = speed of light in given medium
• ———> Refers to the change in angle and speed of light as it changes mediums.
• Snell’s law: the index of refraction (n) is inversely proportional to the sine of the angle of refraction (θ).
• *n1 sin(θ1) = n2 sin(θ2)**
• -> The index of refraction for air is approximately equal to 1
• Thin Lens Equation: 1 / f = 1 / o + 1 / I
• -> f = focal length, o = object distance, i = image distance Used to calculate the focal length of a lens
• Focal length: f = r/2
• -> f = focal length, r = radius of curvature
• Magnification: m = − I / o = hi / ho
• -> m = magnification, i = image distance, o = object distance, hi = image height, ho = object height

-Optical power: The power of a lens refers to the degree to which it converges or diverges light
Power = 1 / f —-> f = focal length

Question 24

Gases:

• -> Ideal Assumptions (2)
• ->Ideal Condition (2)
• -> STP
• Values of sq (2) and sq rt (3)
• Newton’s Three Laws
• Energy–> what is it and the units
• Work: What is it and the units
• Work Energy Theorem
• 4 Laws of Thermodynamics:
• 0th law
• 1st law
• 2nd law
• 3rd law
• Methods of Heat Transfer:
• Conduction, Convection, Radiation

-Processes: Isobaric, Isochoric, Isothermal, Adiabatic

-

Answer 24

• Ideal assumptions: 1) gases occupy no space and 2) gas collisions are perfectly elastic.
• Gases behave like ideal gases at high temperature and low pressure.

-STP: One mole of an ideal gas occupies 22.4 L at standard temperature (273.15 K) and pressure (1 atm)

• Values of sq (2) and sq rt (3):
• Valentines Day is Feb 14 (2/14) –> sq rt (2) = 1.4
• St Patricks Day is March 17 (3/17) –> sq rt (3) = 1.7

Newton’s first law: The law of inertia –> An object at rest will stay at rest, and an object in motion will stay in motion, without an external force.
Newton’s second law: Fnet = m ⋅ a –> A net force acting on an object will cause it to accelerate in the direction of the force.
Newton’s third law: Action-reaction –> Every force has an equal and opposite force.

• Energy: Defined as the capacity to do work. SI unit are Joules
• *1J = 1kg ⋅ m^2 / s^2**

-A force does work if it results in motion in the direction of force. Work measures the transfer of energy.
Unit: Joule —> 1J = 1kg ⋅ m2 s2

-Work Energy Theorem: When energy transfer in a system affects only kinetic energy, net work equals change in kinetic energy.

• 4 Laws of Thermodynamics:
• 0th law: Thermal equilibrium follows the transitive property, ie two systems in equilibrium with a third system will also be in equilibrium with each other.

-1st law: The law of conservation of energy: energy can not be created or destroyed. Expressed by the formula: ΔE = Q + W
—–>∆E = change in energy of a system, Q = heat (negative if heat flows out of system, positive if heat flows in), W = work (negative if work is done by system, positive if work is done on system)
For a gas, W = -P∆V, P = pressure, ∆V = volume

• 2nd law: Total change in entropy will always increase for a spontaneous process.
• 3rd law: Entropy approaches zero as the temperature approaches absolute zero
• Methods of Heat Transfer:
• Conduction = transfer of heat by direct contact
• Convection = transfer of heat by flowing current
• Radiation = transfer of heat by electromagnetic rays –> Can occur in vacuum, does not require flow of matter
• Processes:
• Isobaric: Constant pressure
• Isochoric: Constant volume
• Isothermal: Constant temperature
• Adiabatic: No change in heat

Question 25

• Fluid dynamics:
• Flow type
• —> Laminar vs Turbulent
• —–> Under which conditions is turbulent flow favored?
• Flow rate
• Poiseuille’s law
• Poiseuille’s law formula
• Continuity equation
• Bernoulli’s equation
• Venturi effect
• Pressure Formula
• Pressure Units
• Pressure in a fluid
• Pressure in a gauge
• Atmospheric pressure conversions
• Mercury barometers
• Fluid Physiology:
• Alveoli
• Circulatory System
• Hydrostatic principles:
• Pascal’s principle
• Archimedes’ principle
• -> Submerged fraction and buyoant force
• Specific gravity
• Hydraulic lift

Answer 25

• Fluid dynamics:
• Flow type: Reynolds number determines flow type. Laminar flow occurs at low Reynolds number and turbulent flow occurs at high Reynolds numbers. Turbulent flow is favored over laminar flow under conditions of high velocity and low viscosity.

-Flow rate: Q = Av
Q = flow rate, A = cross sectional area, v = velocity

-Poiseuille’s law: Describes rate of laminar flow
Pressure gradient is inversely proportional to the radius4 and directly proportional to length and viscosity of tubing

• Poiseuille’s law formula: Q = (πr^4ΔP) / (8ηL)
• -> Q = flow rate, ΔP = pressure gradient, r = radius, η = viscosity, L = length
• Continuity equation: Q = A1v1 = A2v2
• -> Fluids flow more rapidly through narrow passages. Think of pinching a garden hose
• Bernoulli’s equation: P1 + 1/2 ρv1^2 + ρgh1 = P2 + 1/2 ρv2^2 + ρgh2
• -> Static plus dynamic pressure is equal at any two points in a system. Pressure decreases as velocity increases.

-Venturi effect: Fluid passing through a constricted area will increase in velocity and decrease in static pressure.

• P = Force / Area
• -> SI unit: Pascal (Pa) , 1 Pa = 1 N^2
• Pressure in a fluid: P = Patm + ρgh
• -> Patm = atmospheric pressure, ρ = density, g = gravity constant, h = height Total pressure in fluid (aka absolute pressure) is atmospheric pressure plus pressure due to the fluid (ρgh)

-Pressure in a gauge: Pgauge = (P0 + ρgh) − Patm
Gauge pressure = Absolute pressure - atmospheric pressure –> This is the reading shown by a pressure gauge instrument.

• Atmospheric pressure conversions: 1 atm = 1 Bar = 101 kPa = 760 mm Hg = 760 Torr
• Mercury barometers: Measures atmospheric pressure by allowing the atmosphere to apply force to one end of a column of mercury –> Measured pressure = F / A, where F is the atmospheric force and A is the cross sectional area of the column of mercury –> Calibrated such that 1 atm = 760 mm Hg
• Fluid Physiology:
• Alveoli: Remember that alveoli are smaller but have greater cross-sectional area compared to larger airways like the trachea.
• -> Compared to the trachea, alveoli have lower flow velocity (think Q = vA) –> Smaller alveoli have lower radii and therefore higher pressures (think Poisueille’s law) and therefore require more surfactant to keep open.
• Circulatory System: In the circulatory system, Q is analogous to cardiac output (CO)
• ->Blood pressure = Q x R = (cardiac output) x (resistance)
• ——-> Example: if there is vasoconstriction, then resistance increases, therefore blood pressure increases.
• Hydrostatic principles:
• Pascal’s principle: Pressure applied to a fluid is transmitted through the entire fluid equally. F / A at point 1 = F / A at any other point in the fluid
• Archimedes’ principle: Fbuoyant = ρV g
• -> ρ = fluid density, V = volume of displaced fluid, g = gravity constant
• *Submerged fraction = object density / fluid density
• *Buoyant force = weight of displaced fluid
• Specific gravity: specific gravity = ρobject / ρwater
• ->Ratio of an object’s density to the density of water
• Specific gravity < 1 indicates that object is less dense and will float in water
• Specific gravity > 1 indicates that object is more dense and will sink in water
• –>Water has a specific gravity of 1
• —-> Density of water is 1000 kg/m^3
• Hydraulic lift: F1 / A1 = F2 / A2
• —-> A machine that applies Pascal’s principle

Question 26

• Nuclear Phenomena:
• Radioactive decay:
• Alpha decay
• Beta decay
• Positron emission
• Electron capture
• Half-life
• Nuclear binding energy:
• Mass deficit
• Nuclear binding energy formula
• Binding energy and mass deficit

Answer 26

• Nuclear Phenomena:
• Radioactive decay: Radioactive decay follows first order reaction kinetics.
• Alpha decay: The loss of an α particle, which is a helium nucleus consisting of two protons and two neutrons.
• Beta decay: Occasionally called “β-negative” decay. –> The decay of a neutron to a proton. Emits a β- particle which is an electron, plus an antineutrino with minimal mass.
• Positron emission: Also known as “β-plus” decay. –> A proton is converted to a neutron. Emits a positron and a neutrino.
• Electron capture: An electron from the inner shell gets absorbed by a proton in the nucleus and forms a neutron.
• Half-life: The amount of time required for a substance to be cut in half by quantity due to decay.
• -> Example: Starting with 100g of a substance with half- life of 1 year. After 1 year you would have 50g, after 2 years 25 g, after 4 years 6.25 g.

-Nuclear binding energy:
-Mass deficit: The mass of the protons and neutrons in an atom is greater than the mass of the atom.
This discrepancy is called mass deficit, and is due to mass converted to binding energy holding the nucleus together

-Nuclear binding energy formula: E = mc^2 –> c = speed of light

• Binding energy and mass deficit: Binding energy = (mass deficit) * c2
• –> This is the amount of energy released in a nuclear fusion reaction.

Question 27

• Electromagnetic Spectrum
• Frequency and Wavelength:
• Radio wave, Microwave, Infared wave, Visible light, UV rays, X-rays, Gamma rays

-Far- and nearsightedness

• Total Internal Reflection
• -> When does it occur?
• –> Critical Angle (formula)
• Electrostatics:
• Charge Movement
• Diamagnetic materials
• Paramagnetic materials
• Ferromagnetic materials
• Circuits:
• Ammeter
• Voltmeter
• Ohmmeter
• Capacitor
• Dielectric Material
• Capacitance in a parallel plate capacitor
• Potential energy of a capacitor
• Currents

Answer 27

• Frequency:
• Radio wave: 10^4
• Microwave: 10^8
• Infared wave: 10^12
• Visible light: 10^15
• UV rays: 10^16
• X-rays: 10^18
• Gamma rays: 10^20
• Wavelength:
• Radio wave: 10^3
• Microwave: 10^-2
• Infared wave: 10^-5
• Visible light: 0.5 * 10^-6
• UV rays: 10^-8
• X-rays: 10^-10
• Gamma rays: 10^-12

-Far- and nearsightedness:
Nearsightedness is corrected by diverging lenses that compensate for over- bending of light rays.
Farsightedness is corrected by converging lenses that compensate for under-bending of light rays

-Total Internal Reflection: When light is reflected back into a medium rather than being refracted. Occurs in scenarios of moving from high index of refraction to low index of refraction –> The minimum angle of incidence to cause total internal reflection is called the critical angle.

–> Critical Angle: the minimum angle of incidence to cause total internal reflection is called
the critical angle: sin(θc) = n2 / n1
θc = critical angle, n = index of refraction

• Charge Movement: Test charges move spontaneously to minimize their electric potential For a negative charge (ie q is negative), they will move toward higher potential. For a positive charge, they will move toward lower potential
• Diamagnetic materials: Diamagnetic materials have no unpaired electrons and are strongly repelled.
• Paramagnetic materials: Paramagnetic materials have some unpaired electrons and are weakly magnetic
• Ferromagnetic materials: Ferromagnetic materials have some unpaired electrons and are strongly magnetic
• Circuits:
• Ammeter: Current, inserted in series
• -> Negligible resistance
• Voltmeter: Voltage change, inserted in parallel
• -> Very high resistance
• Ohmmeter: Resistance, inserted around resistive element
• -> Negligible resistance
• Capacitor: Stores charges
• -> parallel plate capacitors store opposite charges between dielectric

-Dielectric Material: Increases capacitance according to k (constant)

• Capacitance: C = Q / V
• —> C = capacitance, Q = charge, V = voltage
• Capacitance in a parallel plate capacitor: C = kε0 A/d
• -> C = capacitance, k = dielectric constant, ε = permittivity constant, A = area, d = separation distance
• *Capacitance is directly proportional to area of the plates and inversely proportional to separation distance**
• –> Unit of Capacitance is Farad.

Electric Field of Capacitor: E = V / d
–> E = electrical field strength, V = voltage, d = distance between plates

• Potential energy of a capacitor: U = 1/2 C * V^2
• ->C = capacitance, V = voltage
• Currents: The movement of charge between two points.
• *Note that by convention, charge goes from high potential to low potential, but at the atomic level electrons move from low potential to high potential.**

Question 28

Physics Equations Part 3:
-Electrical Potential Energy
-Electric Potential from potential energy (2 equations)
-Electric Field
-Dipole Moment
-Magnetic Field (Force) on Moving charge
-Force of magnetic field on a current-carrying wire
-Coulomb's Law
-Coulomb's constant
-Current formula
-Capacitance in a parallel plate capacitor
-Electric Field of Capacitor
-Potential energy of a capacitor
-Capacitance formula
-Capacitance in series
-Capacitance in parallel
-Resistance
-Resistors in series
-Resistors in parallel
-Ohm's law
-Power in resistors
-Period (T)
-Wave velocity formula
-Angular frequency (ω)
-Intensity
-Doppler effect formula
I-ntensity of sound formula

Answer 28

-Electrical Potential Energy: U = kq1q2 / r
q = charge, k = Coulomb’s constant, r = separation
—> Potential energy due to electrostatic attraction between two charges, measured in Joules. Think of it like “electrical tension.” Increases as like-charges toward each other and decreases with movement away from each other.

-Electric Potential from potential energy: V = U / q = kQ / r
V = voltage, U = potential energy, q = charge, k = Coulomb’s constant, r = separation
—-> Voltage and potential energy are directly proportional to charge.

• Electric Field: E = kQ / r^2
• ->E = electric field strength, k = Coulomb’s constant, Q = charge, r = distance between charges
• —> E = (Force exerted on a test charge) / (magnitude of the test charge)

-Dipole Moment: Dipole moment = q ⋅ d
q = charge, d = separation distance
—->Measures the separation of the charges in a dipole

-Magnetic Field on Moving charge: F = qvB sin(θ)
F = force exerted on charge, q = charge, v = velocity, B = magnetic field

• Force of magnetic field on a current-carrying wire: F = ILB sin(θ)
• –> F = force exerted on wire, I = current, L = length, B = magnetic field

-Coulomb’s law: F = k ∣q1∣ * ∣q2∣ / r^2
F = electric force, k = Coulomb’s constant, q = charge, r = distance of separation

-Coulomb’s constant: k = 9 * 10^9 N * m2 / C2

-Current Formula I = Q / Δt
I = current, Q = charge, Δt = elapsed time

• Capacitance in a parallel plate capacitor: C = kε0 (A / d)
• -> C = capacitance, k = dielectric constant, ε = permittivity constant, A = area, d = separation distance
• *Capacitance is directly proportional to area of the plates and inversely proportional to separation distance**
• Electric Field of Capacitor: E = V / d
• -> E = electrical field strength, V = voltage, d = distance between plates
• Potential energy of a capacitor: U = 1/2 C * V^2
• ->C = capacitance, V = voltage
• Capacitance formula: C = Q / V
• -> C = capacitance, Q = charge, V = voltage

-Capacitance in series: Remember that it’s opposite from resistors, capacitance in series follows same formula as resistors in parallel. The reciprocal of total capacitance is equal to the sum of the reciprocals of individual capacitances.
1 / Cs =1 /C1 +1 / C2 + 1 / C3 +…+1 / Cn

-Capacitance in parallel: Opposite from resistors, capacitance in parallel follows same formula as resistors in series.
The total capacitance is equal to the sum of the individual capacitances
—-> Cp = C1 +C2 +C3 +…+Cn

• Resistance: R = ρ * L/A
• –> ρ = resistivity, R = resistance, A = cross-sectional area, L = length
• Resistors in series: Total resistance is additive and equals sum of all resistors
• -> Rs = R1 +R2 +R3 +…+Rn
• Resistors in parallel: The reciprocal of total resistance is equal to the sum of the reciprocals of the individual resistances Note that the total resistance is always less than the lowest individual resistance
• -> 1/Rp = 1/R1 + 1/R2 + 1/R3 +…+ 1/Rn

-Ohm’s law: V = IR
V = voltage across resistor, I = current, R = resistance
—> Voltage drop across a resistor is directly proportional to the current through the resistor

• Power in resistors: P=IV=V^2/R =I^2 * R
• -> P = power dissipated across resistor, V = voltage, I = current, R = resistance
• Period (T): T = 1 / f
• —–> Number of seconds per cycle.

-Wave velocity formula: v = fλ
λ = wavelength, f = frequency, v = velocity
—–>When applied to light, c = f λ

-Angular frequency (ω): ω = 2πf = 2π / T
ω = angular frequency, f = frequency, T = period, π = radians Measures rate of rotation or oscillation. Units: radians / second.

-Intensity: I = P / A
P = power, A = area. Units: watt / m2

• Doppler effect formula: fo = fs (v±vo) / (v∓vs)
• ——> fo = observed frequency, fs = actual frequency, v = velocity of sound, vo = velocity of observer, vs = velocity of source
• *Velocity of sound = 343 m/s **

-Intensity of sound formula: B = 10 log( I / Io )
Intensity of sound can be given by decibels (B). Io = initial intensity, I = final intensity.
*Intuitive explanation: every increase of 10 decibels multiplies intensity by 10. So an increase of 30 decibels would multiply intensity by 103, or 1000.
———-A level of 0 decibels is equal to an intensity of 1e-12 W/m2
Io is usually 10^-12

Question 29

• Circuits:
• Kirchhoff’s junction rule
• Kirchhoff’s loop rule
• Conductivity
• Resistivity
• Waves and Sound:
• Open pipe
• Closed pipe
• Fixed string
• Transverse versus longitudinal
• Velocity by phase
• –> In Different Phases? In the same phase?
• Attenuation
• Ultrasound
• Interaction of Waves:
• Constructive interference
• Destructive interference
• Standing waves
• Nodes and antinodes
• Resonant frequency

Answer 29

-Kirchhoff’s junction rule: Sum of currents going into a junction equals sum of currents leaving a junction.

• Kirchhoff’s loop rule: The sum of all voltage changes across a loop is equal to zero
• Conductivity: Conductivity (σ) measures the ability of electrons to flow inside a material. Proportional to concentration of charged atoms.
• Resistivity: ρ = R * A / L
• -> ρ = resistivity, R = resistance, A = cross-sectional area, L = length
• Resistivity (ρ) is the inverse of conductivity
• Waves and Sound:
• Open pipe: Two open ends
• —-> λ = 2L / n, where n is number of nodes
• Closed pipe: One open end, one closed end
• —–> λ = 4L / n, where n is number of nodes. n must be an odd integer (ie 1, 3, 5…)
• Fixed string: Two closed ends
• —–> λ = 2L / n, where n is number of antinodes
• Transverse versus longitudinal: Tranverse waves propagate perpendicular to its oscillations while longitudinal waves propagate parallel to oscillations. Light is a transverse wave while sound is a longitudinal wave.
• Velocity by phase: Among phases of matter, sound travels fastest in solids (most “stiff”) and slowest in gases. Within a given phase of matter, such as when comparing a solid to another solid, the relationship works differently: velocity of sound is inversely proportional to density of the medium such that velocity increases as density decreases.
• Attenuation is the loss of intensity as sound travels through a medium Also known as damping. Attenuation increases with greater distance traveled or with more elastic / less dense mediums
• Ultrasound: Ultrasounds produce images by taking advantage of the Doppler effect, with the ultrasound probe as a Stationary observer with velocity of 0. Since the velocity of the observer is 0, the motion of the object being imaged can then be derived from the remainder of the variables in the Doppler equation (difference in frequencies and velocity of sound).
• Interaction of Waves:
• Constructive interference: When two waves interact in phase, the resultant wave will have amplitude equal to the sum of the individual amplitudes.
• Destructive interference: When two waves interact out of phase, the resultant wave will have amplitude equal to the difference of the individual amplitudes.
• Standing waves: Waves that oscillate vertically without traveling horizontally. They are the result of interference from two waves of identical frequency going in opposite directions.
• Nodes and antinodes: Antinodes are the points of maximal displacement or oscillation; nodes are the points of zero oscillation.
• Resonant frequency: When a force is applied at the resonant frequency, it increases the amplitude.
• —-> Example: pushing a person on a swing.
• • Objects, mechanical systems and charged particles tend to vibrate at a specific frequency. We call this frequency the resonant frequency or the natural frequency. When a light or a sound wave strikes an object that is already vibrating at some particular frequency, and if that frequency happens to match the resonant frequency of the object it’s hitting; then you’ll get what’s called resonance. Resonance occurs when the matching vibrations of another object increase the amplitude of an object’s oscillations. **