OCR A A-level Chemistry Year 12

What is valency

The number of electrons in the outer shell of an atom which are able to be used to form bonds with other atoms.

What is the valency of the group 1 elements?

1

What is the valency of the group 2 elements?

2

What is the valency of the group 3 elements?

3

What is the valency of the group 4 elements?

4

What is the valency of the group 5 elements?

3

What is the valency of the group 6 elements?

2

What is the valency of the group 7 elements?

1

What is the valency of the group 8 elements?

0

Why is it hard to judge the valency of transition metals?

they arent in a set group in the periodic table

What is the definition of a hydrocarbon?

A compound containing hydrogen and carbon atoms only

What is the definition of aliphatic?

An organic molecule with straight or branched chains or non-benzene ring

What is the definition of alicyclic?

An organic molecule containing a non-benzene ring

What is the definition of aromatic?

An organic molecule containing a benzene ring

What is the definition of unsaturated?

An organic molecule containing at least one double carbon bond

What is the definition of saturated?

An organic molecule containing only single carbon bonds

What is a homologous series?

A series of molecules with the same functional group which differ by CH2 of each successive member

What are the five ways to group hydrocarbons?

aliphatic, alicyclic, aromatic, alkene, alkane

What is the definition of an alkane?

A molecule with only single carbon bonds

What is the definition of an alkene?

An unsaturated hydrocarbon containing Carbon-carbon double bonds

What is the name of the alkane with 1 carbon?

methane

What is the name of the alkene with 2 carbons?

ethane

What is the name of the alkene with 3 carbons?

propane

What is the name of the alkene with 4 carbons?

butane

What is the name of the alkene with 5 carbons?

pentane

What is the name of the alkene with 6 carbons?

hexane

What is the name of the alkene with 7 carbons?

heptane

What is the name of the alkene with 8 carbons?

octane

What is the name of the alkene with 9 carbons?

nonane

What is the name of the alkene with 10 carbons?

decane

What is the prefix for a molecule with an alcohol group?

hydroxy-

What is the suffix for a molecule with an alcohol group?

-ol

What is the suffix for a molecule with an aldehyde group?

-al

What is the suffix for a molecule with an alkane group?

-ane

What is the suffix for a molecule with an alkene group?

-ene

What is the suffix for a molecule with a carboxylic acid group?

-oic acid

What is the prefix for a molecule containing a haloalkane group?

iodo-, chloro-, bromo-

What is the suffix for a molecule containing a ketone group?

-one

What is Markowni Koff's Rule?

A halogen will prefer the more substituted carbon because a major product is more stable as all hydrogen atoms are on one side

What is the difference between a major and minor product?

major- all hydrogen atoms are on one side

minor- hydrogen atoms on both sides

What does a primary alcohol consist of?

an alcohol group on a carbon bonded to only one other carbon atom

What does a secondary alcohol consist of?

an alcohol group on a carbon bonded to two other carbon atoms

What does a tertiary alcohol consist of?

an alcohol group on a carbon bonded to three other carbon atoms

What's the difference between permanent and temporary dipoles?

permanent- significant difference in electronegativity

temp- spontaneous and due to the chance that electrons are more concentrated in one area of a compound

What happens to the solubility from primary to tertiary alcohols and why?

the solubility increases because there are more

O-H bonds to react with water molecules

What is the definition of esterification?

a process that makes an ester and requires gentle heating and an acid catalyst

What happens when you oxidise a primary alcohol?

oxidises twice

What is made when you oxidise an alcohol under distillation?

aldehyde

What is made when you oxidise an alcohol under reflux?

carboxylic acid

What are the conditions required for oxidation?

reflux/distillation, K2Cr2O7, heat, H+ from H2SO4

What does K2Cr2O7 stand for?

acidified potassium dichromate

What is reflux?

A technique that involves condensing vapours

What is distillation?

the action of purifying a liquid by a process of heating and cooling.

What happens when you oxidise a secondary alcohol?

oxidises once

What is made when you oxidise a secondary alcohol?

ketone

Why are tertiary alcohols resistant to oxidation?

it is too difficult to remove carbon atoms

What is the test for oxidation?

use potassium dichromate

What happens to potassium dichromate when a substance as been oxidised/not oxidised?

oxidised- turns from orange to green

not oxidised- stays orange

Does electronegativity or bond enthalpy have a bigger impact on the rate of hydrolysis for haloalkanes?

bond enthalpy

How does the boiling point of haloalkanes differ from alkanes and alcohols?

lower than alcohol but higher than alkanes

Why is the boiling point of haloalkanes higher than alkanes?

more electrons, increasing dipole and stronger van der waals, so more energy required

Why is the boiling point of haloalkanes lower than alcohols?

alcohols contain hydrogen bonds, which are the strongest intermolecular force, and require lots of energy to break

What happens when haloalkanes are in an aqueous solution?

a nucleophillic substitution reaction occurs

What are the two properties of CFC's?

chemically inert, non-toxic

What do CFC's stand for?

Chlorofluorocarbons

What are the 4 uses of CFC's?

fridge coolants, aerosols, fire extinguishers, air conditioning coolants

What are the 4 problems of UV light?

sunburn, premature ageing, skin cancer, cataracts

What is the definition of cracking?

breaking down large hydrocarbons into smaller, more useful hydrocarbons

What are the conditions for cracking?

high temperature and pressure

What is the definition of the ozone layer?

an area of high concentration of ozone in the stratosphere

What is the definition of a radical?

a highly reactive species with one or more unpaired electrons

What are the conditions for polymerisation?

high temperature and pressure

What is the definition of mass spectrometry?

a technique that helps identify the amount and type of chemical present in a sample by measuring the mass-to-charge ratio and the abundance of gas phase ions

What is the definition for electronegativity?

how likely does an atom, in a covalent bond, want to attract electrons

What type of bond is made when there is no electronegativity, slight EN and large EN?

no EN- covalent bond

slight EN- polar covalent bond

large EN- ionic bond

What is the definition of empirical formula?

the simplest whole number ratio of atoms of each element in a compound

What is the definition of molecular formula?

the actual number of atoms of each element in a compound

What is the definition of skeletal formula?

a diagram that shows only key functional groups in a molecule

What is the definition of structural isomerism?

molecules with the same molecular formula but different structural formula

What is the definition of stereo-isomerism?

molecules with the same molecular and structural formula but different arrangement of atoms

What is the difference between chemical bonds and intermolecular forces?

chemical bonds- hold molecules together and are broken

intermolecular forces- within molecules and are overcome

What are the two physical properties of alkanes?

insoluble in water, fairly unreactive

Why are alkanes fairly unreactive?

they contain no double bond, so there is a higher activation energy

Why do bigger molecules have higher boiling points?

more intermolecular forces, more electrons, bigger dipole, stronger van der waals, more energy needed to overcome

Why do branched molecules have lower boiling points?

atoms/electrons are further apart, decreased dipole, decreased strength of van der waals, so less energy needed to overcome

Why are branched chains used as fuels?

more efficient combustion

What are the three steps in free radical substitution?

initiation, propagation, termination

What condition is required in the initiation step of free radical substitution?

UV light

What type of bond fission occurs in the initiation step of free radical substitution?

homolytic fission

What is the definition of incomplete combustion?

burning without enough oxygen

What products does incomplete combustion make?

carbon monoxide, water

What is the problem with incomplete combustion?

carbon monoxide is poisonous, odorless, carcinogenic, colourless

What is the definition of complete combustion?

burning with enough oxygen

What products are made in complete combustion?

water, carbon dioxide

What is the name and bond angle of alkenes?

120, trigonal planar

What is the name and bond angle of alkanes?

109.5, tetrahedral

What is the test for saturation?

bromine water

What happens when alkene and alkanes are added to bromine water?

alkene- orange to colourless and clear

alkane- stays orange solution

Why does the colour of bromine water differ for alkenes and alkanes?

alkane+Br2--->alkane+Br2

alkene+Br2-->dibromoalkane

haloalkane is colourless

What are the 5 ways of disposing of polymers?

organic feedstock, recycle, reuse, landfill, combustion