1.16 calculate relative formula masses (Mr) from relative atomic masses (Ar)

RELATIVE FORMULA MASS (Mr):

- It is just all the relative atomic masses added together.
- MgCl2 is just 24 + (35.5 x 2) = 95
- C2H4(OH)2 is just (12 x 2) + (1 x 4) + ((16 + 1) x 2) = 62