Question

Nitromethane (CH3NO2) burns in air to produce significant amounts of heat. 4 CH3NO2 (l) + 3 O2 (g) → 4 CO2 (g) + 6 H2O (l) + 2 N2 (g) , ΔHorxn = -2836 kJ If 1,273 kJ of heat are produced from the burning of nitromethane, how many grams of nitromethane were burned?

Answer 1

Answer:

27.38 g

Explanation:

• CH₃NO₂ (l) + 3O₂ (g) → 4CO₂ (g) + 6H₂O (l) + 2N₂ (g)   ΔHorxn = -2836 kJ

The value of ΔHorxn tells us that when 1 mol of CH₃NO₂ is burned, 2836 kJ of heat are produced. With that in mind we can calculate how many moles of CH₃NO₂ were burned when 1273 kJ of heat were produced:

• 1273 kJ * 1mol / 2836 kJ = 0.4489 mol

Then we convert 0.4489 moles of CH₃NO₂ to grams, using its molar mass:

• 0.4489 mol * 61 g/mol = 27.38 g