IGCSE Calculations Test
30 marks
1.
Name ________
(a)What is the mass of one mole of sodium [1]
(b) What is the mass of two moles of Mg(OH)2 [2]
(c) How many moles is 50g of CaCO3[2]
2. (a) What is the empirical formula of C6H6? [1]
(b) What is the empirical formula of a compound that contains
57.5% Na, 40% O and 2.5% H (show your working)? [3]
(c) If a compound has empirical formula CH3 and an RFM of 45 what
is its molecular formula? [2]
3. If 1.2g of magnesium was added to excess sulphuric acid (H2SO4),
what mass of magnesium sulphate was produced?[3]
Mg+ H2SO4  MgSO4 + H2
4. Calculate the mass of ammonia (NH3) produced when 280g of nitrogen
react with plenty hydrogen [3]
N2
+
3H2
5. Define Relative Atomic Mass [2]

2NH3
6. What is the Relative Atomic mass of Magnesium which has the isotopes
24
Mg at 78.6% abundance, 25Mg at 10.1% abundance and 26Mg at 11.3%
abundance. [2]
7. What is the percentage of sodium in Na2CO3 [2]
8. A hydrated compound has the following formula: Na2SO4.xH2O
An experiment heated 3.22g of the hydrated compound and 1.8g of
water was driven off. What is the value of x? [3]
9. (a) What is the concentration of a solution made from 4 moles
dissolved in 100cm3 of water? [1]
(b) What is the concentration of a solution made from 234g of NaCl
dissolved in 2000cm3 of water? [2]
(c) How many moles is 200cm3 of a 0.25moldm-3 solution? [1]