Activity 3.6:
Calculating the number of moles and mass
[Relative atomic mass: H = l, C = 12, N = 14, O = 16, Mg = 24, S = 32, Fe = 56; Avogadro constant, NA : 6.02 × 1023 mol–1]
1. Calculate the mass of each of the following substances:
(a) 0.4 mol of iron fillings, Fe
(b) 2.2 mol of carbon monoxide, CO
2. Calculate the number of moles in each of the following substances:
(a) 49 g of sulphuric acid, H2SO4
(b) 8.88 g of magnesium nitrate, Mg(NO3)2
3. An experiment requires 0.05 mol of ammonium sulphate crystals, (NH4)2SO4. What is the mass of ammonium sulphate, (NH4)2SO4 that should be used?
4. 0.2 mol of substance Y has the mass of 11 g. What is the molar mass of substance Y?
Answer:
1. (a) 22.4 g
(b) 61.6 g
2. (a) 0.5 mol
(b) 0.06 mol
3. 6.6 g
4. 55 g mol–1
Calculating the number of moles and mass
[Relative atomic mass: H = l, C = 12, N = 14, O = 16, Mg = 24, S = 32, Fe = 56; Avogadro constant, NA : 6.02 × 1023 mol–1]
1. Calculate the mass of each of the following substances:
(a) 0.4 mol of iron fillings, Fe
(b) 2.2 mol of carbon monoxide, CO
2. Calculate the number of moles in each of the following substances:
(a) 49 g of sulphuric acid, H2SO4
(b) 8.88 g of magnesium nitrate, Mg(NO3)2
3. An experiment requires 0.05 mol of ammonium sulphate crystals, (NH4)2SO4. What is the mass of ammonium sulphate, (NH4)2SO4 that should be used?
4. 0.2 mol of substance Y has the mass of 11 g. What is the molar mass of substance Y?
Answer:
1. (a) 22.4 g
(b) 61.6 g
2. (a) 0.5 mol
(b) 0.06 mol
3. 6.6 g
4. 55 g mol–1