Chemistry AQA GCSE Paper 2

combustion

hydrocarbon reacts with oxygen to produce carbon dioxide and water

conditions of fermentation

30 degrees with no oxygen

source of hydrogen

reacting methane with steam

colour of phenolphthalein in acid

colourless

colour of phenolphthalein in alkali

pink

breaking bonds is …

endothermic

test for water

cobalt chloride paper

catalyst for haber process

iron

colour change in cobalt chloride paper

blue-pink

overall energy transferred =

energy needed for breaking bonds - energy needed for making bonds

what reaction happens in a chemical cell?

displacement

when the difference in reactivity between metals in a chemical cell is greater, what is also greater?

current

hydrogen fuel cells use …

hydrogen and oxygen

in a hydrogen fuel cell the hydrogen is …

oxidised

hydrogen fuel cell negative electrode

hydrogen splits

hydrogen fuel cell positive electrode

water is formed

rate of reaction =

change in mass / time taken

rate of reaction in a gas =

change in volume / time taken

le chateliers principle states that ..

equilibrium will shift depending on conditions

long chain hydrocarbons

low flammability, high boiling point and viscosity

short chain hydrocarbons

high flammability, low boiling point and viscosity

general formula of alkanes

CnH2n+2

saturated

no double bond

unsaturated

double bond

general formula for alkenes

CnH2n

chemical test for alkenes uses …

bromine water

hydrogenation is … (word equation)

alkene + hydrogen = alkane

why are alkenes not used as fuels?

produce a smoky flame, incomplete combustion

general formula for alcohols

CnH2n+1OH

ethanol is formed by the process of …

fermentation

ethanol can also be formed by …

hydrating ethene

what happens when alcohols react with sodium?

forms an alkoxide

general formula for carboxylic acids

CnH2n+1COOH

carboxylic acids are formed by …

oxidising alcohols

esters are formed by reacting …

carboxylic acids and alcohols

which type of polymerisation produces generally biodegradeable products?

condensation

amine functional group

HN2

what is formed when the same type of amino acid react?

polypeptides

what is formed when different amino acids join?

proteins

what is created when two amino acids join

peptide link

what is the repeating monomer in DNA?

nucleotide

structure of DNA

phosphate sugar base

base A pairs with

T

base G pairs with

C

formation

a substance designed for a specific purpose

mobile phase

solvent

stationary phase

paper

solvent front

where the solvent travels to

Rf value =

distance moved by substance / distance moved by solvent

gas test for hydrogen

lit splint in test tube with a squeaky pop

gas test for oxygen

blown-out splint in test tube which will relight

gas test for carbon dioxide

bubble gas through limewater which will turn cloudy

gas test for chlorine

blue litmus paper will turn white

gas test for ammonia

red litmus paper will turn blue

flame test colour of lithium

pink/red

flame test colour of sodium

yellow/orange

flame test colour of potassium

purple

flame test colour of calcium

orange/red

flame test colour of copper

green

sodium hydroxide test for Al 3+

white precipitate, dissolves

sodium hydroxide test for Ca 2+

white precipitate

sodium hydroxide test for Mg 2+

white precipitate

sodium hydroxide test for Cu 2+

blue precipitate

sodium hydroxide test for Fe 2+

green precipitate

sodium hydroxide test for Fe 3+

brown precipitate

test for carbonate

solution mixed with hydrochloric acid and gas sent into limewater tube which will turn cloudy

test for halides

add to silver nitrate and nitric acid

halide test results for chlorine

white precipitate

halide test results for bromine

cream precipitate

halide test results for iodine

yellow precipitate

test for sulfate

hydrochloric acid and barium chloride, white precipitate forms

NMR is used to determine

molecular structure

IR is used to determine

the type of bonds

Mass Spectroscopy is used to determine

mass

what is limewater

calcium hydroxide

composition of the atmosphere 2.7b to 200m years ago

less carbon dioxide, more oxygen and nitrogen

% carbon dioxide concentration currently

0.04

% oxygen concentration currently

20

% nitrogen concentration currently

80

source of water vapour

combustion

sulfur dioxide causes…

acid rain

sulfur dioxide is prevented by …

taking out all sulfur from fuel before burning it

nitrogen oxides cause…

acid rain, health problems

nitrogen oxides are prevented by …

using a catalytic converter

carbon dioxide is produced from

complete combustion

soot particles are formed from

incomplete combustion

soot particles cause

global dimming

soot particles are prevented by..

using catalytic converter

carbon monoxide is formed by

incomplete combustion

salt water can be treated by

desalination and reverse osmosis

process of sewage water treatment

screening and grit removal, sedimentation, aerobic treatment of effluent, anaerobic treatment of sludge, biogas, sludge dried and burnt

phytomining

plants absorb copper from soil and burnt

bioleaching

bacteria breaks bonds between ions in metal ore

life cycle assessments - RMUD

raw materials, manufacturing, use, disposal

electroplating

covering one metal with another to prevent corrosion

bronze

copper and tin

use of bronze

statues

brass

copper and zinc

use of brass

musical instruments

high carbon steel

iron with 1-2 percent carbon