Question

Ammonium nitrate decomposes explosively upon heating according to the following balanced equation:
2NH4NO3(s)→2N2(g)+O2(g)+4H2O(g)

Part A

Calculate the total volume of gas (at 116 ∘C and 763 mmHg ) produced by the complete decomposition of 1.66 kg of ammonium nitrate.

Answer 1

Molar mass of NH4NO3 = 2*MM(N) + 4*MM(H) + 3*MM(O)

= 2*14.01 + 4*1.008 + 3*16.0

= 80.052 g/mol

mass of NH4NO3 = 1.66 Kg

= 1660 g [using conversion 1 Kg = 1000 g]

we have below equation to be used:

number of mol of NH4NO3,

n = mass of NH4NO3/molar mass of NH4NO3

=(1660 g)/(80.052 g/mol)

= 20.74 mol

From reaction,

2 mol of NH4NO3 produces 7 mol of gas

so,

moles of gas formed = 7*20.74/2 = 72.59 mol

we have:

P = 763 mm Hg

= (763/760) atm

= 1.0039 atm

n = 72.59 mol

T = 116 oC

= (116+273) K

= 389 K

we have below equation to be used:

P * V = n*R*T

1.0039 atm * V = 72.59 mol* 0.0821 atm.L/mol.K * 389 K

V = 2309 L

Answer: 2.31*10^3 L