number of particles = number of moles × 6.02 × 10²³

relative formula mass is relative molecular mass but for ionic compounds

gases and volatile liquids follow the ideal gas equation under standard conditions

for percentage atom economy calculations use the big numbers

high percentage atom economy =

• little to no waste product, only the desired product, so more economically viable for industrial scale manufacture

• less natural resources used so less energy used so beneficial for the environment

improving percentage atom economy:

• cannot be improved.

• sell the by-product to increase profits.

transition metals can form different ions so have variable oxidation states thus they can be used as catalysts to lower the activation energy of a chemical reaction.

in the Solvay Process, ammonia is not considered a raw material because:

• ammonia is used up but then regenerated later in the cycle

• no overall consumption of ammonia

• can act as a catalyst

in the Ostwald Process, excess air is used to:

• ensure all the ammonia is used up/ensure a complete reaction or combustion.

• maximise the yield of nitric acid.

when heated, iron(Il) nitrate is converted into iron(lll) oxide, nitrogen dioxide and oxygen:

4Fe(NO₃)₃(s) —> 2Fe₂O₃(s) + 12NO₂(g) + 3O₂(g)

this reaction is thermal decomposition.

the iron(III) oxide is pure because:

• the other products are gases/escape easily.

• there’s no other solid (or liquid) product.

it is hard to separate 2 solids/liquids/gases produced by a reaction, which makes it difficult to obtain a pure sample

percentage yield of a product may decrease if:

• the product is a gas so easily escapes.

• the reaction is incomplete.

• not all reacts.

• there are by-products.

• impure reactants are used.

• there are side reactions.