Given the balanced equation of H2SO + O2 → H2SO3, how many liters of O2 are needed to produce 2.5 x 102 g H2SO3 at standard temperature and pressure?

Answer 1

Hello, Angie,

250 grams of H₂SO_3, with a molar mass of 82.1 g/mole, represents 3.05 moles of H₂SO₃.

The balanced equation

H2SO + O2 → H2SO3

tells us we need 1 mole of O₂ for every 1 mole H₂SO₃. That's a molar ratio of 1/1. To produce 3.05 moles of H₂SO₃ we need 3.05 moles of oxygen. To find the volume of this number of moles of a gas, use the ideal gas law, PV = nRT.

Rearrange for the unknown, V:

V = nRT/P

I use a value of R, the gas constant, of 0.08206 L*atm*K^-1mole^-1.

Temnperature and pressure are standard, which is 1 atm pressure and 273.15K temperature. Now enter the data:

V = (3.05 moles)*(0.08206 L*atm*K^-1mole^-1)*(273.15K)/(1 atm)

V = 68.4 liters at STP

Bob