work out how many atoms of each element are in the chemical formula add together the A r values for all the atoms of each element ...

Relative formula masses can be calculated and used ... of solution and uncertainties in measurements. Calculations in chemistry - Higher - AQA The mole is the unit for amount of substance.

like Hess’s law and the standard enthalpy of reaction is good too,” he says. Moses recommends practising A-level or HKCEE papers for certain topics, such as equilibrium and organic chemistry.