PROBLEM 118P

Ammonium nitrate decomposes explosively upon heating according to the balanced equation:

2 NH4NO3(s) → 2N2(g) + O2(g) + 4 H2O(g)

Calculate the total volume of gas (at 25 °C and 748 mm Hg) produced by the complete decomposition of 1.55 kg of ammonium nitrate.

Solution 118P

Here, we are going to calculate the total volume of gas produced by the complete decomposition of 1.55 kg of ammonium nitrate.

Step 1: Given reaction is

2 NH4NO3(s) → 2N2(g) + O2(g) + 4 H2O(g)

2.0 mol 1.0 mol 1.0 mol 4 mol

Thus, 2.0 mol of NH4NO3(s) produces = 1.0 mol +1.0 mol + 4.0 mol = 7.0 mol gas

Step 2: Calculation of the total amount of gas.

Total mass of NH4NO3(s) = 1.55 kg = 1550 g

Molar mass of NH4NO3(s) = 80.04g/mol

Amount of NH4NO3(s) = Mass/molar mass = 1550 g/ 80.04g/mol = 19.36 mol

Thus 19.36/2 mol or 9.68 mol of NH4NO3(s) produces = 7.0 x 9.68 mol gas = 67.778 mol

Therefore, 67.778 mol of total gases produced by 1.55 kg of ammonium nitrate