Chemistry Basics Flashcards
Periodic Table Properties
How do you determine electron configuration for an ionized element?
- Find electron configuration for natural element
- remove e- from (1) p orbital, then (2) s orbital and finally (3) d orbital.
You remove electrons from the outer most shell.
Ex:
[Ar]4s23d10 = Zn
[Ar]3d10 = Zn2+
What is a Lewis Acid?
What is a Lewis Base?
Lewis Acid: a species that accepts an electron pair (i.e., an electrophile) and will have vacant orbitals
Lewis Base: a species that donates an electron pair (i.e., a nucleophile) and will have lone-pair electrons
What are the similarities between Cu+ and Zn2+? How could scientist seperate the two?
Same: Number of e-
Even though the two have the same number of e-, they have different charges because they have a different number of protons (ions do not change proton number). This means (1) difference in ionic radius AND (2) nuclear size. They will also experience different (3) electrostatic force from an outside charge because they cary different charges.
What are the three important eq. to know for Gibbs Free energy passages?
ΔG = ΔH - TΔS
ΔG0=−RTlnK
ΔG of rx= (sum of ΔG formation of products) - (sum of ΔG formation of reactants)
Define Decarboxylation
The loss of a CO2 group in a rx
What is an amine? What about amino and amide?
An amine is basically an ammonia derivative where one or more hydrogen atoms has been replaced by an organic substituent. When an amine is considered as the functional group of a molecule, it is referred to as an “amino group”.
Amide: carbonyl carbon and a nitrogen in a carbon chain
A tertiary amine is an amine in which the Nitrogen is attatched to three carbons; secondary is attatched to two carbons ect…for determining whether an alcohol fnx group is primary/secondary, look in flashcards for biochem
What is an alcohol fnx group?
What is a phenol fnx group?
R-OH
ph-OH
What is the difference between an Ether and Ester fnx group?
What is an aldehyde fnx group?
What about a Ketone fnx group?
What is a carboxylic acid?
What is the fnx group Nitrate?
NO3-
What is the difference between a solution and a suspension?
A solution is a HOMOGENOUS mixtureof two substances (solvent and solute) and is considered homogenous becayse its apperance and composition is uniform throughout.
A suspension is a HETEROGENEOUS mixture of larger particles that are visible and will settle out after the mixture stands. (ex. a powerder is undissolved in a solution and makes a suspension of particles that are larger than the size of an individual molecule= colloid)
Compare and contrast an electrochemical cell and an electrolytic cell
Electrochemical (Galvanic ie HUMAN) cell: Cathode (+) is the intermembrane space and the anode (-) is in the matrix.
An Ox: oxidation happens at anode
Red Cat: reduction happens at cathode
Ecell=Ecathode-Eanode (Think CAT-AN, the game)
Electrolytic cells (gel electrophoresis): Needs electrical energy source to move non spontaneous redox rx. Cathode (-) and anode (+). In a gel electrophoresis, we put sample on cathode end and negative DNA fragments flow towards the anode.
Enantiomers
Molecules that are mirror images of one another (configurational isomers)
They have identical physical properties and almost all chemical properties except optical activity. There is only one enantiomer per molecule.
Connects to: L/D nomenclature for carbohydrates. By definition L and D sugars have inverted stereochemistry at all chiral carbons and thereore are enantiomers. (People digest D formation). (when trying to determine cyclic form of sugar looking at only the linear form. Which way the -OH group furthest from the carbonyl is facing? “DOWNRIGHT, UPLIFTING” Meaning, if OH is on the right, then it will be facing down in cyclic form, and if it is on the left, it will be facing up in the cyclic form)
Diastereomers
Configurational isomers with more than one stereocenter that are nonsuperimposable and not mirror images.
They have different chemical and physical properties
Structural (constitutional) isomers
Same molecular formula (same molecular mass) but different structure (connected differently)
Different structures means different physical and chemical properties.
Constitution of the united states: All states are made up of the same parts, but connected VERY differently.
Stereoisomers
Have the same connectivity but are arranged differently in space
Conformational and configurational are two stereoisomers
Conformational-same molecule rotated around a single bond. They conform ie the most similar.
Meso Compouds
Compounds that have more than one chiral center but also have internal plane of symmetry
Heterocycles
Hetero=different, cyclic=ring. Heterocycles are molecules with atoms other than carbon in a ring
Homocycles=molecules made of only carbon in a ring
Stereocenter
Connected to three different substituents
Disproportionation
Disproportionation describes a reaction where a species is simultaneously oxizides and reduced.
What stabilizes and destabilizes a free radical?
stabilize: resonance (double bonds), lone pairs, bigger atoms
destabilize: high electronegativity, e withdrawing group
Tautomers
Tautomers are two molecules with the same molecular formula but different connectivity - constitutional isomers, in other words - which can interconvert in a rapid equilibrium. The most common tautomeric relationship in organic chemistry is the keto-enol pair.
ex. acetone (CH3OCH3) predominately in ketone form
Protic/Aprotic
protic: has OH or NH or FH/SH bond(s) to participate in H bonding
aprotic: cannot participate in H bonding
A solution can be polar and aprotic (ex. acetone)
What interactions contribute to tertiary protein structure?
How can you tell is a reaction is stereospecific?
Stereospecific means the reaction preferentially produces a particular stereoisomer. (80% one type and 20% the other).
If a passage just tells you it forms two isomers, assume it is not stereospecific.
What functional group is formed when two amino acids react to form a peptide bond?
Amide
i.e carbonyl carbon linked to a nitrogen
Think C and N terminus combining
Difference between inter and intra
Intramolecular forces are the forces that hold atoms together within a molecule. Intermolecular forces are forces that exist between molecules.
What is the nmonic to remember enzymes?
LILHOT
LI: Ligases and isomerases (affect bonding of molecules)
LH: lyases and hydrolases (cleave molecules)
OT: oxidoreductases and transferase (shuttle)
What stabilizes carbocations?
resonance
- double or triple bonds c=c nearby
- atoms with unpaired electrons that can donate their electrons for stability
high e- withdrawing groups would make the + even more + and that’s not cool
How do you calculate formal charge on atoms?
formal charge= number of valence e- an atom “should” have from the periodic table -sticks (bonds) - dots (unpaired e-)
how do you find the equilibrium constant from a reaction?
Keq=products/reactants
aA + bB = cC + dD
[C]c[D]d/[A]a[B]b
leave out solids !
did the oxidation of X change in the reaction? How do you figure this out?
- is X in an acid or base? yes= acid/bases do not change oxidation states
- no=is X in standard state? ex CO2 yes=state is zero
- monoatomic ions=charge
- sum of chanrges in polyatomic ions=charge on molecule
