Stoichiometry I

How to find the percentage of composition of mass of an element in a compund?

Relative molecular mass of element / Telative molecular mass of compound X 100

Molecular formula (Definition)

A formula which shows the number and type of each atom present in a molecule of that compound

Empirical formula (Definition)

The formula showing the simplest whole number ratio of the numbers of different atoms present in the molecule

Molecular formula and empirical formula formula

Molecular formula = Empirical Formula X n

What does empirical formula X n equal to to find n?

Relative molecular mass of element / Telative molecular mass of compound X 100

How to find the molecular formula when given percentages of each element in a compound?

Percentage of each element / Relative molecular mass. Out of all the elements find the smallest mole ratio found from the calculations and divide each by the smallest one found. Solve using empirical formula X n = molecular formula

How to find the empirical formula when given percentages of each element in a compound?

Percentage of each element / Relative molecular mass. Out of all the elements find the smallest mole ratio found from the calculations and divide each by the smallest one found. Each number found corresponds with the amount of molecules of that atom in the compound

How to find empirical formula given the masses of reactants and product?

Mass of product - mass of reactant. Divide by Mr to find moles of the elements of the compound and simplify them as a ratio

How to find masses of reactants or products from a balanced chemical equation?

Find their corresponding masses and make it up to the mass in the question.

How to find the volumes of gases from balanced chemical equations?

Same method as finding the mass of non-gaseous compound except 1 mole of the gas = 22.4L at s.t.p or 24L at room temp