Question

Consider the reaction: 2SO2(g)+O2(g)→2SO3(g). If 288.7 mL of SO2 reacts with 150.7 mL of O2 (both measured at 312 K and 77 mbar) What is the theoretical yield of SO3?

Answer 1

Volume of SO₂ = 288.7 mL = 0.2887L

VOlume of O₂ = 150.7 mL = 0.1507 L

Temperature (T) = 312K

Pressure (P) = 77 mbar =0.07599 atm

Gas constant (R) = 0.0820 L.atm/mol.K

Ideal gas equation is

PV = nRT

Moles of SO₂ are

n = 0.07599 atm * 0.2887L / ( 0.0820 L.atm/mol.K * 312K) = 8.57*10^-4 mol

Moles of O₂

n = 0.07599 atm * 0.1507L / ( 0.0820 L.atm/mol.K * 312K) = 4.47 *10^-4 mol

NOw, reaction is :

2 SO2 +    O2 2 SO3

2 mol 1 mol 2 mol

Thus, 8.57*10^-4 mol of SO₂ reacts with 8.57*10^-4 mol/2 = 4.28 * 10^-4 mol of O₂

So, SO₂ is a limiting reagent.

From reaction

2 mol of SO₂ gives 2 mol of SO₃

Thus, 8.57*10^-4 mol of SO₂ gives 8.57*10^-4 mol of SO₃

thus, theoretical yield of SO₃ is 8.57*10^-4 mol