320320 gg of solid ammonium nitrite, NH_4NO_2NH4NO2, decomposes when heated according to the balanced equation: NH_4NO_2 -> N_2+2H_2ONH4NO2N2+2H2O. What total volume of gases at 819819 KK is emitted by this reaction?

1 Answer
Mar 21, 2016

Each mole of NH_4NO_2NH4NO2 produces 33 molmol of gases total (N_2N2 and H_2OH2O), and we have 55 molmol. So 3xx5 = 153×5=15 molmol of gas at STP is 336336 LL. Converting to 819819 KK gives a volume of 10081008 LL.

Explanation:

The molar mass of NH_4NO_2NH4NO2 is 6464 gmol^-1gmol1 (two NN at 1414, four HH at 11, two OO at 1616).

Find the number of moles of NH_4NO_2NH4NO2:

n=m/M=320/64=5n=mM=32064=5 molmol

From the balanced equation, each mole of NH_4NO_2NH4NO2 yields 1 mole of N_2N2 and 2 moles of H_2OH2O (which is definitely a gas at 819819 KK), for a total of 3 moles of gas.

For ideal gases (which we can treat these real gases as for our purposes), 1 mole of any gas at STP (273273 KK and 11 atmatm) occupies 22.422.4 LL.

That means we have 3xx5 = 153×5=15 molmol of product gases, and they occupy a volume of 336336 LL at STP.

We need to change the temperature from 273273 KK to 819819 KK, and the pressure stays the same at 11 atmatm, so:

V_1/T_1=V_2/T_2V1T1=V2T2

Rearranging:

V_2=V_1T_2/T_1 = 336 xx 819/273 = 1008V2=V1T2T1=336×819273=1008 LL