Question

CH₄ +2 O₂ = CO₂ + 2 H₂O

You burned 15.0 grams of methane (CH4) in an excess of oxygen and formed 23.8 grams of water. What was your percent yield, rounded to 3 sig-figs?

Answer 1

Molar mass of methane $=16g/mol$

Molar mass of water $=18g/mol$

Moles of methane burned$=\frac{15}{16}=0.9375$ moles

Moles of water $=0.9375×2$

$=1.875$

Mass of water $=1.875×18$

$=33.75g$

$\%$ yield $=\frac{23.8}{33.75}×100\%$

$=70.5\%$