If 4.8 mol H2O2 decomposes, what volume of oxygen will be produced? (assume the density of oxygen is 1.429 g/L)

Question

2H2O2 (aq) --> 2H2O (I) + O2 (g)

Answer 1

Hello, Grace,

The balanced equation tells us that we'll get 1 mole of O₂ for every 2 moles of H₂O₂. That's a molar ratio of 1/2, so we'll get half of the moles of H₂O₂ that we started with.

(4.8 moles H₂O₂)*(0.5)=2.4 moles O₂

Convert 2.4 moles O₂ to grams by multiplying by it's molar mass (32 g/mole). That gives us 76.8 grams O₂.

Normally, I'd be concerned about the pressure/temperature of a gas, but we're given the density, which we will have to assume is correct for the conditions of the gas.

Density = 1.429 g/L

O₂ = 76.8 grams

Volume = 76.8 grams/(1.429 g/L) = 53.74 liters

Sounds like a lot, but one mole of any gas at STP occupies 23.4 liters. (2.4 moles)*(23.4L/mole) = 53.76 liters, so I think we're good. Or, at least, reasonable.

Bob