GCSE Double Award Chemistry
Non Metal summary
GASES
Gas
Formula Reactant
Reactant
Test
(solution)
(solid)
Hydrogen
H2
Sulphuric
Zinc
Pops a lighted
acid
splint
Zn + H2SO4 = ZnSO4 + H2
Oxygen
O2
Hydrogen
Manganese
Relights a glowing
peroxide
oxide (catalyst) splint
2H2O2 = O2 + 2H2O
Carbon
CO2
Hydrochloric Calcium
Turns limewater
dioxide
acid
carbonate
milky
(marble chips)
CaCO3 + 2HCl = CaCl2 + H2O + CO2
Chlorine
Cl2
Bleaches litmus
Nitrogen
N2
No test
H2, O2, Cl2 & N2 are diatomic gases – 2 identical atoms held by a covalent bond
Hydrogen
1. Hydrogen burns in air to form water – releases lots of energy, used as a fuel.
2H2 + O2 = 2H2O
2. Hydrogen is a REDUCING agent – takes away oxygen.
It reacts with black copper oxide to form copper metal & steam, know the
diagram and observations
CuO + H2 = Cu + H2O
3. Hydrogen reacts with nitrogen to form ammonia N2 + 3H2 = 2NH3
This is an important industrial process called the Haber Process.
Conditions are very important – 450oC, 250atm, iron catalyst
These conditions are a compromise to ensure the rate and yield is adequate
Uses of ammonia – making fertilizers, dyes, nylon & explosives
Oxygen
Oxygen is important for burning, breathing and rusting reactions.
All are classed as oxidation reactions. Only 1/5th, 21% of the air is made up of oxygen.
1. Combustion is burning, substances are converted to make oxides -see class
‘burning’experiment. Metals form basic oxides, non-metals form acidic oxides.
GCSE Double Award Chemistry
Non Metal summary
Water is a neutral oxide and aluminium & zinc are amphoteric ie. both acidic and
basic. Compounds also form their oxides when they burn:
Methane + oxygen = carbon dioxide + water
CH4 + 2O2 = CO2 + 2H2O
2. Breathing is RESPIRATION.
Glucose + oxygen = carbon dioxide + water
3. Rusting is the oxidation of iron in the presence of water.
Rust is hydrated iron III oxide, look up the methods used to prevent rust.
Carbon Dioxide
1. Carbon dioxide is an acid gas, it dissolves in water to form a weak acid known as
carbonic acid H2CO3.
H2O + CO2 = H2CO3
(Look up its role in Hard water)
2. Carbon dioxide reacts with sodium hydroxide to form a white crust of sodium
carbonate
NaOH + CO2 = Na2CO3 + H2O
3. Carbon dioxide is a greenhouse gas and contributes to global warming – know effects
Chlorine
Chlorine is a pale green toxic gas, it has many uses as a disinfectant – know all uses
It is made from the electrolysis of seawater (brine), the chloro-alkali industry
Sodium chloride + water ---------------Hydrogen+ chlorine + sodium hydroxide
(cathode) (anode)
Chlorine will displace bromides & iodides, they will change to display their colour.
Chlorine + sodium bromide = bromine + sodium chloride
Green gas colourless solution =red/orange solution
Cl2 + 2NaBr = Br2 + 2NaCl
Chlorine + sodium iodide = iodine + sodium chloride
(colourless to brown)
Cl2 + 2NaI = I2 + 2NaCl
GCSE Double Award Chemistry
Non Metal summary
Nitrogen
Nitrogen is an unreactive gas, it has a triple bond so too much energy is needed to break
the bond. Know uses.
Ammonia NH3 as above
WATER
Water is a covalent molecule – draw it out.
Water is essential to all life
Water of crystallisation is the water bonded inside a crystal.
Salts with water are Hydrated, when the water is removed are Anhydrous
Hydrated Copper sulphate crystals = anhydrous copper sulphate + water
CuSO4.5H2O = CuSO4 + 5H2O
Blue
white
Anhydrous copper sulphate is used as a chemical test for water;
colour change white to blue
Water pollution is caused by fertilisers, detergents and sewage – read up effects
Sulphur
Sulphur is a yellow solid, it has a low melting point, is insoluble in water and a poor
conductor of electricity.
Sulphur is found in volcanic areas and is an impurity in fossil fuels (acid rain).
1. Sulphur burns with a blue flame to form fuming sulphur dioxide
S + O2 = SO2
2. Sulphur reacts with metals to form metal suphides (experiment)
This is an exothermic reaction that glows red even when the heat is removed
Fe + S = FeS
The oxides of sulphur form strong acids; SO2 forms sulphurous acid, H2SO3
SO3 forms sulphuric acid, H2SO4
Acid rain is caused by the acidic gases released by burning fossil fuels & erupting
volcanoes; sulphur dioxide & sulphur trioxide are examples. It affects Scandinavian
countries most due to prevailing winds blowing the acidic gases north & due to the cold
conditions increasing the solubility of the gases.
Acid rain has many negative environmental effects; kills plants, kills fish, removes
nutrients from soil, corrodes buildings and statues, etc
Acid rain must be reduced by: Burning less fossil fuels,Desulphurising fossil fuels
 Cleaning (scrubbing) exhaust gases by lining chimneys with limestone
 Using alternative energy sources