Q1.

In an experiment, ammonia gas is made by heating a mixture of ammonium chloride and calcium

hydroxide.

2NH4Cl (s) + Ca (OH) 2 (s) =

CaCl2 (s) + 2NH3 (g) + 2H2O (l)

10.0 g of ammonium chloride is added to an excess of calcium hydroxide.

Calculate the maximum volume of ammonia gas that could be formed.

(relative atomic mass H = 1.00, N = 14.0, 0 = 16.0 and Ca = 40.0; one mole of any gas occupies 24 dm

at room temperature and pressure)

121

4.49dm3

Explanation:

2NH4Cl + Ca (OH) 2 - > CaCl2 + 2NH3 + 2H2O

First, we need to convert 10g of ammonium chloride to mole. This is illustrated below:

Molar Mass of NH4Cl = 14 + (4x1) + 35.5 = 53.5g/mol

Mass of NH4Cl = 10g

Number of mole = Mass / Molar Mass

Number of mole of NH4Cl = 10/53.5 = 0.187mol

From the equation,

2moles of NH4Cl produced 2 moles of NH3.

Therefore, 0.187mol of NH4Cl will also produce 0.187mol of NH3

Now we can obtain the volume of NH3 produced by doing the following:

1mole of any gas occupy 24dm3

Therefore, 0.187mol of NH3 will occupy = 0.187 x 24 = 4.49dm3