Question

6a/ A sample of gas contains 0.1500 mol of N₂(g) and 0.3000 mol of O₂(g) and occupies a volume of 18.9 L. The following reaction takes place: N₂(g) + 2O₂(g) 2NO₂(g)
Calculate the volume of the sample after the reaction takes place, assuming that the temperature and the pressure remain constant (.......) L

6b/ A sample of gas contains 0.1200 mol of NH₃(g) and 0.1500 mol of O₂(g) and occupies a volume of 12.5 L. The following reaction takes place: 4NH₃(g) + 5O₂(g) 4NO(g) + 6H₂O(g)

Calculate the volume of the sample after the reaction takes place, assuming that the temperature and the pressure remain constant (........) L

6c/ A sample of gas contains 0.1000 mol of OF₂(g) and 0.1000 mol of H₂O(g) and occupies a volume of 6.52 L. The following reaction takes place: OF₂(g) + H₂O(g) O₂(g) + 2HF(g)

Calculate the volume of the sample after the reaction takes place, assuming that the temperature and the pressure remain constant (.......) L

Answer 1

1)

1) given that,

initial volume (V₁) = 18.9 L

Number of moles of N₂= 0.1500 mol

number of moles of O₂ = 0.3000 mol

thus,total initial moles (n₁) = 0.2000 + 0.4000 = 0.4500 moles

total intial moles n1 = 0.4500 mol

Reaction is :
N2 + 202 ---> 2N02

from the above reaction

moles of NO₂ formed = moles of O₂ reacted

moles of NO₂ formed = 0.3000 mol

thus, total final moles( n₂) = 0.28

now, from avogadros law ( equal volume of all gases at constant pressure and temperature contains same number of molcules),

V/n = constant

V1/n1 = V2 / n2

18.9 / 0.4500 = V2 / 0.3000

V2 = 12.6 L

hence, the volume of the sample after the reaction takes place = 12.6 L