Answer is: the percent yield is 56.85%.
Chemical reaction: CH₄ + 2O₂ → CO₂ + 2H₂O.
m(CH₄) = 987 g.
n(CH₄) = m(CH₄) ÷ M(CH₄).
n(CH₄) = 987 g ÷ 16 g/mol.
n(CH₄) = 61,68 mol.
From reaction: n(CH₄) : n(CO₂) = 1 : 1.
n(CO₂) = 61,68 mol.
m(CO₂) = 61,68 mol · 44 g/mol.
m(CO₂) = 2714,25 g ÷ 1000 g/kg = 2,714 kg.
yield = 1,543 kg ÷ 2,714 kg · 100 % = 56,85%.
