Chemical calculations

How is the relative atomic mass of an element found?

↳ Number at the top

↳ Usually higher

How do you work out relative atomic mass (M_r)?

↳ Add al the relative atomic masses together (top number)

What is Avogrado’s constant?

↳ One mole of substance contains

6.02 × 10²³ atoms,ions or molecules

How do you work out moles?

↳ Mass ÷ M_r (add top numbers)

How do you work out concentration?

↳ Mass ÷ volume

How do you convert cm³ to dm³

↳ Divide by 1000

How do you work out the mass of product formed given the mass of a reactant?

↳ Balance the equation

↳ Work out moles (Mass ÷ M_r)

↳ Mass= moles x M_r (add top numbers)

How do you balance an equation given the masses of reactants and products?

↳ Work out M_r (add top numbers)

↳ Work out moles (Mass ÷ M_r)

↳ Convert to the simplest whole number ratio

↳ Balance symbol equation

How do you work out which reactants are in excess?

↳ Balance the equation

↳ Work out moles

↳ Compare moles

↳ Lower- limiting

↳ Higher- excess