Question

A type of anthracite contains 90% carbon by weight. How much co2 is produced from the combustion of 1 metric ton of this anthracite? How much co2 is produced from the combustion of 1 mcf (1,000,000 ft3 at standard conditions) of propane?

Answer 1

1) Chemical reaction: C + O₂ → CO₂.

m(anthracite) = 1 t · 10⁶g/t = 10⁶ g.

ω(C) = 90% ÷ 100% = 0.9.

m(C) = ω(C) · m(antracite).

m(C) = 0.9 · 10⁶ g = 9·10⁵ g.

n(C) = m(C) ÷ M(C).

n(C) = 9·10⁵ g ÷ 12 g/mol.

n(C) = 75000 mol; amount of substance.

From chemical reaction: n(C) : n(CO₂) = 1 : 1.

n(CO₂) = 75000 mol.

m(CO₂) = 75000 mol · 44 g/mol.

m(CO₂) = 3300000 g = 3300 kg = 3.3 t; mass of carbon dioxide.

2) Chemical reaction: C₃H₈ + 5O₂ → 3CO₂ + 4H₂O.

V(C₃H₈) = 10⁶ ft³ · 0.02833 m³/ft³.

V(C₃H₈) = 28330 m³ = 22330000 L.

Vm = 22.4 L/mol; standard volume of ideal gas.

n(C₃H₈) = 22330000 L ÷ 22.4 L/mol.

n(C₃H₈) = 996875 mol.

From chemical reaction: n(C₃H₈) : n(CO₂) = 1 : 3.

n(CO₂) = 2,990,625 mol.

m(CO₂) = 1.3·10⁸ g.