Question

The mass composition of dry paper is 43% carbon, 6% hydrogen, 44% oxygen, and 7% other. Estimate the volume of air required to burn 1 kg of dry paper, assuming complete combustion at 20°C and 1 atm.

Answer 1

C + O₂ ----> CO₂

2H₂ + O₂ ----> 2H₂O

there is 1000 g of the compound

Thus, mass of C = 430 g

moles of C = mass/molar mass = 430/12 = 35.833

Thus, moles of O₂ required for complete combustion of C = moles of C = 35.833

mass of H = 60 g

Moles of H₂ = mass/molar mass = 60/2 = 30

Thus, moles of O₂ required = (1/2)*moles of H₂ = 15

mass of O present = 440 g

Thus, moles of O₂ present in the compound = mass/molar mass = 440/32 = 13.75

Total moles of O₂ required = 35.833 + 15 - 13.75 = 37.083

Thus, volume of O₂ required = (n*R*T)/P = (37.083*0.0821*293)/1 = 892.04 litres