Unit 4 AOS 1 Flashcards
What is the valency of the Carbon atom
4
How many outer shell electrons does carbon have
4
Nature of C-C bond
strong and stable
Prefixes for halogens
chloro, idodo, bromo, fluoro
What is the functional group for ketones
carbonyl group
How do you label an alkene/alkyne with more than one bond
di, tri, tetra
What can’t C=C bonds do
rotate
What are the groups called for trans and cis isomers
hetero groups
What does it mean if you can draw a line of symmetry in compound
it’s achiral
What reactions can alkenes undergo
substitution, photochemical substitution
What is photochemical substitution equation for with Cl
alkane + Cl (UV) = haloalkane + HCl
What should be added to hydrocarbon to form amino group
ammonia
Formula for ammonia
NH3
What happens when you add water to alkene + catalyst
OH and H are added into hydrocarbon
What type of catalyst is necessary for addition of water to alkene
acidic catalyst
What is needed to react H2 with alkene
catalyst, e.g. Pt
What reaction can a secondary alcohol undergo
oxidation to form ketone
What reactions can a primary alcohol undergo
oxidation to form aldehyde, esterification
What reactions can a carboxylic acid undergo
can be reacted with amine to form amide and water, esterification
What can’t tertiary alcohols react to form
ketone, aldehyde, carboxylic acid
What is needed for esterification to occur
concentrated H2SO4 (liquid) and all of the reactants must be in liquid state
What is necessary for hydrolysis of an ester
water, H+
What is organic chemistry
study of carbon-containing compounds (usually containing C-H bonds and excluding compounds such as cyanide, carbon oxides and carbonates - as they are inorganic compounds)
What are hydrocarbons
compounds containing only carbon and hydrogen atoms
Explanation for covalent bonds in carbon
The electronegativity of carbon is too low for a carbon to attract electrons from another element to form a negative ion and it is too high to release electrons to another element to form a positive ion
What are covalent bonds
Bonds between two or more non-metal atoms involving the sharing of electron pairs between atoms.
Are carbon compounds relatively stable
yes
Why can carbon form double bonds/rings
they are of a small size so can get close enough
Why can carbon form bonds and chains of various lengths
covalent bonds with self
Second best atom for this
silicon
Why are carbon compounds diverse
because can form 4 bonds
What is bond energy
the measure of the amount of energy needed to break apart 1 mole of covalently bonded molecules in the gaseous state
Why organic chemistry is important
drugs/medicine, agriculture, industrial applications
What are natural compounds
carbohydrates, protein, fats/oils, hydrocarbons, enzymes, vitamines, alkaloids
What are carbohydrates needed for
source of energy in food
What are proteins needed for
source of compounds for growth and repair of tissues in body
What are the applications of fats and oils/role in the body
source of energy found in food, stored in body, used in cooking, soaps
hat are Hydrocarbons used for
fuels, petrol, cooking
What are enzymes
complex protein molecules found in plants and animals, catalysis of biochemical reactions
Where are alkaloids found
found in variety of compounds including medicines
Synthetic compounds examples
soaps/detergents, antibiotics, polymers
What are aliphatic compounds
Describes organic compounds in which carbon atoms form open chains.
Aromatic compounds
Describes a compound that contains at least one benzene ring and is characterised by the presence of alternating double bonds within the ring.
Alkanes
saturated, simple carbon compounds containing only single bonds
General formula for Alkanes
CnHn+2
Saturated hydrocarbons
Hydrocarbons containing only single carbon–carbon bonds and they cannot take up any more hydrogens.
Unsaturated hydrocarbons
Hydrocarbons containing at least one double carbon–carbon bond.
Bond angle of methane
109.5 degrees
Homologous series
A series of organic compounds that have the same structure but in which the formula of each molecule differs from the next by a CH2 group.
Use of methane
fuel
Use of ethane
manufacture of ethene
Use of propane
fuel, aerosols
Use of butane
fuel, aerosols
Formulas in which compounds can be written
molecular, empirical, structural, semi-structural/condensed, skeletal, 3D structural
Structural isomers
Molecules that have the same molecular formula but different structural formulas.
Alkenes
The family of hydrocarbons that contain one carbon–carbon double bond.
What is ethene known as
ethylene
Alkynes
The family of hydrocarbons with one carbon–carbon triple bond.
Cyclohexane
A pungent saturated cyclic hydrocarbon C6H12 found in petroleum.
General formula of cycloalkanes
CnH2n.
Aliphatic compound example
cycloalkanes
Benzene
An aromatic hydrocarbon with the formula C6H6. Lack of reactivity, high stability and same bond lengths between the carbon atoms.
Benzene is used for
used to produce food, pharmaceuticals but is carcinogenic
Simplest homologous series
alkanes
Functional group
- group of atoms attached to or part of a hydrocarbon chain that influence the physical and chemical properties of the molecule. Determines function of compound.
Is a compound with or without a functional group more stable
without as if a functional group is attached, it is more likely to react
Do compounds with functional groups form a homologous series
yes
Hydroxyl group
OH functional group
Alcohols/alkanols
hydrocarbons containing the OH functional group
Carboxyl group
the COOH functional group, which has weakly acidic properties.
Carboxylic acids
Hydrocarbons containing the COOH functional group
Alcohol functional group
hydroxyl
Alcohol suffix
ol
Aldehyde functional group
aldehyde (HC=O)
Aldehyde suffix
al
Ketone functional group
carbonyl (C=O)
Ketone suffix
one
Carboxylic acid functional group
carboxyl (COOH)
Carboxylic acid suffix
oic acid
Ester functional group
ester (OCO)
Ester suffix
alkyl alkanoate (alcohol carboxylic acid)
Ether functional group
ether (R-O-R)
Amine functional group
amine/amino NH2
Amine suffix
amine
Amide functional group
amide (O=CNH2)
Amide suffix
amide
Primary alcohol
C-OH is attached to one other carbon atom
Secondary alcohol
C-OH is attached to two other carbon atoms
Tertiary alcohol
C-OH is attached to three other carbon atoms
What is a property aldehydes are known for
smell
What do the low molecular weight aldehydes smell like
unpleasant
What do high molecular weight aldehydes smell like
pleasant
Uses of aldehydes
perfumes, solvents, manufacture of plastic, dyes, pharmaceuticals
Uses of carboxylic acids
making soaps and polyesters, found in foods
Ester
An organic compound formed from a condensation reaction between an alcohol and a carboxylic acid.
Ester is used in
paints, perfumes, cosmetics, artificial flavourings found in fruits
Primary, secondary and tertiary amines determined by
how many C connected to N
Amine called … if high functional group
amino if higher functional group
Amide uses
solvents in a variety of pharmaceuticals, creating nylon and other polymers, to colour crayons/pencils
Priority for naming scale
carboxylic acid > ester > amide > aldehyde > ketone > alcohol > amine > alkyne=alkene > alkane
Organic reactions
reactions that take place between organic compounds
Types of organic reactions
Addition, decomposition, combination, substitution, rearrangement
3 types of intermolecular forces
dispersion forces, dipole-dipole attractions and hydrogen bonding
What are physical properties affected by
size, shape structure and degree of polarisation of molecules
Simple organic compounds are generally (what state)
gases, volatile liquids or solids with low melting and boiling points (because intermolecular forces are weak)
What is the strength of dispersion forces affected by
shape and size of molecules
Isomers
two or more compounds with the same molecular formula but different arrangements of atoms
Structural isomers
Molecules that have the same molecular formula but different structural formulas.
When do isomers have different physical and chemical properties
when different functional group
Why do isomers have different physical and chemical properties when there is a different functional group
Functional isomers have different intermolecular forces and distinctly different properties.
Three types of structural isomers
chain isomers, positional isomers, functional isomerism.
Chain isomer
A type of structural isomer that involves more branching.
In chain isomers, more branched isomers have lower boiling points. Could be because more spherical and has less surface area for the dispersions forces to act.
Positional isomers
Isomers where the position of the functional group differentiates the compounds.
What does the position of the functional group affect
compactness and polarity
Functional isomers
Isomers containing different functional groups.
Stereoisomers
Two or more compounds differing only in the spatial arrangements of their atoms. The atoms are connected in the same order but are oriented differently in space
Types of stereoisomers
cis and trans isomers, enantiomers or optical isomers
Cis-trans isomers
types of stereoisomers that are formed when the same two different groups are bonded to each of the carbon atoms in a carbon-carbon double bond. A cis isomer has identical groups on the same side of the double bond; a trans isomer has the groups on opposite sides.
Is cis or trans stronger
cis (e.g in trans the dipoles may cancel out)
Does trans or case have higher boiling points
cis is higher
Does trans or cis have a higher melting point
trans is higher as they can pack more closely
Can trans and cis occur in rings
yes
Chiral
Describes compounds containing an asymmetric carbon atom or chiral centre. The molecule cannot be superimposed upon its mirror image.
Chiral centre
An asymmetric carbon atom.
Enantiomers
Chiral molecules that are non-superimposable mirror images of one another.
Are enantiomers symmetrical
no
Are the physical/chemical properties the same for enantiomers
physical properties are identical (except for optical activity) and their chemical properties are generally the same, but they react differently with other molecules that have optical properties.
What it’s called when it’s not chiral
achiral
What is necessary for something to be achiral
2 or more groups attached to tetrahedral are the same
What are the states of alkanes
first 4 are gases, because as the size of the molecule increases, so does the influence of the dispersion forces; therefore, the melting and boiling points increase.
What affects boiling point
dispersion forces, degree of branching
Does branching increase or decrease boiling points
decrease due to the inability of molecules to get closer to each other; as the dispersion forces operate over a small distance only, the attraction is diminished.
What is viscosity
A measure of a fluid’s resistance to flow
The viscosity of liquid alkanes increases with…
the number of carbon atoms
What increases viscosity
n.o. intermolecular forces, branched molecules becoming tangled
What happens to viscosity as temp increases
decreases because have enough energy to overcome forces
What is flashpoint
The temperature at which a particular organic compound gives off sufficient vapour to ignite in air. Of volatile liquid is the lowest temperature at which the liquid gives off enough vapour to start burning at its surface on application of an ignition source. Below the flashpoint, there is not enough vapour available to support combustion.
What is a flammable liquid
is any liquid with a flashpoint below 38.7 degrees
Liquids classified as combustible are (in terms of if they are flammable or not and why)
harder to ignite and have a flashpoint of 37.8 and above
At what temperatures do flammable liquids ignite and burn easily - at lower temperatures. Combustible liquids can burn at temperatures that are usually above room temperature. It is not actually the liquid that burns; it is the mixture of its vapours that burns in the oxygen in the air.
Do smaller hydrocarbons have high or low flashpoint
low, as have weaker bonds and are more flammable
Are alkanes or alkenes more reactive
alkenes due to double bond
Are alkynes generally flammable
yes
What does adding halogen do to strength/polarity
more polar, stronger bonds.
Why do alcohols have higher boiling points than alkanes
OH group so hydrogen bonding + dipole-dipole
Are alcohols soluble in water
smaller ones are
Does alcohol boiling point increase with n.o. carbons
yes because of dispersion forces
Does solubility of alcohol increase with n.o. of carbons
no due to more non-polar sections of the molecules
Are alcohols highly flammable
yes
Do volatility/flammability decrease as the alcohol molecules increases
The flammability of alcohols decreases as the molecules increase in size and mass due to the increased strength of attraction between the molecules. Volatility also decreases as the size of the molecule increases.
Are carboxylic acids soluble
first are very soluble due to hydrogen bonding,
Do carboxylic acids or alcohols have higher boiling points
carboxylic acids due to more hydrogen bonding
Are carboxylic acids strong/weak acids
weak as they only partially ionise
Are aldehydes and ketones volatile
yes (no hydrogen bonds)
Does solubility increase with ketones and aldehydes with n.o carbon
no
Do esters have a higher booing point than carboxylic acids
no as they cannot form hydrogen bonds with each other as there is no OH bond
Does solubility increase with carbon n.o.
no
Are amines weak or strong acids or bases
weak base
Do amines have a higher boiling point than alcohol
no
What is states of amine
first 2 are gases, rest are liquids
Does solubility increase with carbon n.o.
no
Alkanes are fairly…
un-reactive: they do not dissolve in water, nor react with acids/bases
Substitution reaction
Reactions in which one or more atoms of a molecule are replaced by different atoms.
What is cracking
The process of breaking down complex chemical compounds by heating them. A process that uses heat and pressure, and sometimes a catalyst, to break larger hydrocarbon molecules into smaller molecules, including an alkene and hydrogen, or an alkane.
What are addition reactions
Reactions in which one molecule bonds covalently with another molecule without losing any other atoms. In addition reactions for alkenes, the double bond is broken, and new single bonds are formed. This is because the energy required to break the double bond is less than the energy released in the formation of two single bonds.
How to test for unsaturation
add bromine to alkene
What is needed to make ethene into ethanol
ethene + steam (H2O) = ethanol
What is polymerisation
A process of reacting monomer molecules together in a chemical reaction to form polymer chains.
What is a monomer
A molecule that links with other monomers to form a polymer.
How to form polyethene
use addition polymerisation of ethene
What is addition polymerisation
The process in which monomers with at least one double bond react together to form a polymer by addition reactions.
What is a polymer
Giant molecules formed by repeated monomers that have been joined by covalent bonds.
Acidified permanganate formula
H+/MNO4- (aq)
Acidified dichromate formula
H+/Cr2O72- (aq)
O2 (with a catalyst) can be added to alcohols to form
carboxylic acids and H2O is formed as a product
What are condensation reactions
Reactions in which molecules react and link together by covalent bonding with the elimination of a small molecule, such as water or hydrogen chloride, from the bond that is formed.
Polyesters are formed as a result of
ester linkages between monomers to form the polymer. In the formation of a polyesters, water is removed for every monomer (except for one water). Not necessarily ester monomer, just bonding.
% yield formlula
% yield = mass of product/theoretical mass * 100
Atom economy is
method for measuring the efficiency of a reaction that takes into account the amount of waste produced. The atom economy of a reaction considers the amount of useful product produced from a particular amount of reactants.
% atom economy formula
% atom economy = mass of atoms in desired product/mass of atoms in reactants X 100
What is chromatography used for
to separate the components of a mixture and to identify the components
What is qualitative analysis
An investigation used to identify the presence or absence of elements, ions or molecules in a sample. (What is in a substance)
What is quantitative analysis
An investigation used to determine the amount of a given element or compound.
What is spectroscopy
The investigation and measurement of spectra produced when matter interacts with or emits electromagnetic radiation.
Types of spectroscopy
mass spectrometry, NMR spectroscopy, IR spectroscopy
What is mass spectrometry
The investigation and measurement of the masses of isotopes, molecules and molecular fragments by ionising them and determining their trajectories in electric and magnetic fields.
What happens in mass spectrometry
molecules are bombard with high-energy electrons causing them to fragment and lose electrons, resulting in positive ions formed
Base peak
The most abundant/common ion in a mass spectrum - assigned a height of 100 - highest on the graph
Why is it the most common
most stable or can be formed in different ways
If there is a mass of 15 what is the fragment likely to be
methyl group
What is infrared spectroscopy
Describes spectroscopy that deals with the infrared region of the electromagnetic spectrum.
Do all objects emit IR radiation
yes
Why is infrared radiation used
as it is either emitted or absorbed by molecules when the bonds change their vibrational movements
What happens to the vibrational energy during IR spectroscopy
goes from the ground state to the excited state. A molecule can move from a lower to a higher vibrational energy level if it absorbs an amount of energy equal to the difference between levels.
What happens to the wave number as the wave length increases
it decreases
The more complicated the region on IR below 1000cm-1…
the more complex the molecule
Why is there a CH2 group near the OH in ethanol
because the OH is pulling it towards itself
What does NMR stand for
nuclear magnetic resonance
What two compounds can be used in NMR
13C and 1H
What happens when an external magnetic field is applied
the spinning nuclei either align with the external field or align against it
Which one has the higher energy level (either with or against)
against
What does applying radio waves do
causes the nucleus to flip which releases energy
Basis of NMR
the amount of energy required to change its spin state depends on the environment type
Main types of NMR
carbon-13 NMR, low-resolution proton NMR (H1), high-resolution proton NMR (H1)
What does TMS stand for
tetramethylsilane (CH3)4Si
Is NMR quantitative or qualitative
qualitative
What does the number of peak sets tell us
the number of unique environments
What does the chemical shift tell us
information about the functional groups involved
What does the n.o of sub-peaks/area under peak set tell us
n.o of H present in neighbouring environments
What is the scale for 13CNMR
0-250ppm
What is the scale for 1HNMR
0-13ppm
What is it called when you analyse relative area under each peak set
integral trace
Rule to determine n.o of H in adjacent environment
n+1 rule
What does HPLC stand for
high performance liquid chromatography
What is the mobile phase
The liquid or gas that flows through a chromatography system, moving the materials to be separated at different rates over the stationary phase.
What is the stationary phase -
A solid with a high surface area, or a finely divided solid coated with liquid. It shows different affinities for various components of a sample mixture when separating them by chromatography.
What is used in paper chromatography
usually cellulose or filter paper covered with water or ethanol
What is used in thin-layer chromatography
finely divided adsorbent material is coated onto either a glass slide or aluminium foil to form stationary phase and liquids are used for mobile phase
What is adsorption
The adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface.
What is desorption
The removal of a substance from or through a surface; the opposite of adsorption.
What is generally used as a stationary phase for HPLC
narrow column that is packed tightly with a finely divided powder (high SA)
Examples of powders used
alumina or silica
What is an eluent
A substance used as a solvent in separating materials.
What is a sample
what is being analysed
What are analytes
The components of a sample.
What is retention time
The time taken for each component of a sample to travel from the injection port to the end of the column.
Area under each peak shows…
amount/concentration of substance
Normal-phase liquid chromatography
mobile phase is non-polar and stationary phase is polar
Reverse-phase liquid chromatography
mobile phase is polar and stationary phase is non-polar
What is most commonly used in HPLC
reverse-phase
What are the axes for calibration curve
peak area is the y axis and concentration is the x axis
What is likely to be compound if it evolves H2 when mixed with Mg
carboxylic acid
Volumetric analysis
Determination of the concentration, by volume, of a substance in a solution, such as by titration. Quantitative analysis.
pH formula
pH = -log10[H3O+] concentration
Hydronium/OH formula
[H3O+][OH-]=Kw where Kw = 1.010^-14
What is a pipette
instrument used to accurately measure or transfer small quantities of liquid
What is the aliquot
unknown concentration
What is the titrant
solution of known concentration
What is the burette
A graduated glass tube for delivering known volumes of a liquid, especially in titrations.
What is titration
Process used to determine the concentration of a substance by using a pipette to deliver one substance and a burette to deliver another substance until they have reacted exactly in their mole ratios.
What is the titre
The volume delivered by a burette.
2 types of titration
acid-base and redox
What is the standard solution
A solution that has a precisely known concentration.
What are the two methods of determining the concentration
reacting it with other solution whose concentration is known accurately (standardisation) or dissolving a primary standard into a known volume of water
What is the primary standard
A substance used in volumetric analysis that is of such high purity and stability that it can be used to prepare a solution of accurately known concentration.
Primary standards must be…
abundant, accurately known formula, high state of purity, cheap and readily available, relatively high molar mass,
Why shouldn’t NaOH be used
absorbs moisture, reacts with CO2
Why shouldn’t hydrated sodium carbonate
unsuitable as it loses water to atmosphere but can be heated to remove water then used
What is the volumetric flask used to contain
primary standard
What is the equivalence point
Where two reactants have reacted in their correct mole proportions in a titration.
What is the end point
The experimentally determined/approximated equivalence point at which the indicator just changes colour or the pH curve becomes vertical. Occurs after slight excess.
Titration curve
Curve used to measure the volume of a titrant against pH.
Concordant titres
Describes titres that are within a defined volume of each other, such as 0.10 mL.
Concentration formula using mol and volume
n=cV
Concentration formula using volumes
c1V1=c2v2
What is a diprotic acid
can donate 2 protons
What is a monoprotic acid
can donate 1 proton
What is a polyprotic acid
can donate more than 2 protons
What is an amphiprotic acid
can donate or accept protons
What is the retention time for large molecules
higher retention time
What is the retention for molecules that are soluble in mobile phase
shorter retention time
What are the axes for chromatogram
y axis is absorbance and x axis is retention time in minutes
What does elution rate mean
how fast it is passed out of column
Order of elution in normal phase in order of first elution to last
alkanes/alkenes, esters, alkyl halides, alcohols, carboxylic acids. It also goes shortest chain to longest chain.
What is the wavelength symbol
ʎ m
What is the wavelength in terms of the graph
the period of the graph
What is wave number proportional to
frequency
What happens if the frequency increases
the wavelength decreases and the energy of a photon increases
Formula for wave number
wavenumber = 1/wavelengthcm-1
What do large wavelengths mean
small wave numbers
What is the absorbance relative to
the concentration
Formula for delta E for NMR
delta E = hv where hv is radio energy
In NMR where is polar and where is shield thickness
low energy and polar is the left and left to right is decreasing shield thickness
What shape is the titration curve
S-shaped
Why is no indicator required for redox titration
as there is usually a colour change
What are the axes for IR
the y axis is transmittance and the x axis is the wave number
What are the names for the number of sub-peaks in NMR
singlet, doublet, triplet, quartet,
Formula for Rf
Rf=distance travelled by component/distance travelled by solvent
What does Rf stand for
retardation factor
What are the units for Rf
no units
What will titration curve look life for strong acid-weak base titration
fairly spread out titration S-shaped curve
What will titration curve look life for weak-acid strong base titration
very un-spread out (vertically)
What does strong acid and strong base form + pH
extremely weak conjugate base and extremely weak conjugate acid - pH of 7
What does strong acid and weak base form + pH
extremely weak conjugate base and weak conjugate base - pH is over 7
What does weak acid and strong base form
extremely weak conjugate acid and weak conjugate acid - pH less than 7
What is the tallest peak called in mass spectroscopy
base peak
What does the parent ion/peak tell us in mass spectroscopy
the molecular mass
What is the charge for all the ions on mass spectrum
+ 1
What does IR show
functional groups
Basis of IR
amount of IR absorbed depends on type of bond
What is the wave length for stronger bonds
higher wave length
What does the mass spectroscopy tell us
molecular formula
What is high resolution NMR
when it has sub-peaks that tell you n.o of H
What is low resolution NMR
no sub peaks
