recall and explain the main features of the particle model in terms of the states of matter and change of state, distinguishing between physical and chemical changes and recognise that the particles themselves do not have the same properties as the bulk substances
**explain the limitations of the particle model in relation to changes of state when particles are represented by inelastic spheres **
use ideas about energy transfers and the relative strength of forces between particles to explain the different temperatures at which changes of state occur
use data to predict states of substances under given conditions
interpret evidence for how it is thought the atmosphere was originally formed
describe how it is thought an oxygen-rich atmosphere developed over time
describe the major sources of carbon monoxide and particulates (incomplete combustion), sulfur dioxide (combustion of sulfur impurities in fuels), oxides of nitrogen (oxidation of nitrogen at high temperatures and further oxidation in the air)
explain the problems caused by increased amounts of these substances and describe approaches to decreasing the emissions of these substances into the atmosphere including the use of catalytic converters, low sulfur petrol and gas scrubbers to decrease emissions
use chemical symbols to write the formulae of elements and simple covalent compounds
use the names and symbols of common elements and compounds and the principle of conservation of mass to write formulae and balanced chemical equations
use arithmetic computations and ratios when balancing equations
describe tests to identify oxygen, hydrogen and carbon dioxide PAG2
explain oxidation in terms of gain of oxygen