Chemistry Moles

What is a mol?

The unit for the amount of substance

Formula for moles

Moles = Mass/Mr

Formula for percentage yield

Actual yield/theoretical yield X 100

Formula for concentration

Concentration = Moles/Volume

Formula for volume

Volume = Moles x 24

How to work out the percentage mass of an element in a compound?

Atomic mass x Number of atoms / Molecular mass of the whole compound X 100

What is empirical formula?

Empirical formula is the simplest whole number ratio of the atom type in the substance

What is molecular (chemical) formula?

Molecular (chemical) formula tells us how many of each type of atom is in the substance

How to work out molecular formula from empirical formula?

• Divide the relative formula mass of the molecular formula by the relative atomic mass of the empirical formula

• Multiply each number in empirical formula by this number

How do you turn cm³ into dm³?

Divide by 1000