Hydrocarbon weighing 112g is burned in air to produce 328.5 g of carbon dioxide what percent mass of carbon in the hydrocarbon

80.0 %

Explanation:

As per the law of conservation of mass all the mass of carbon present in the hydrocarbon weighing 112 g is present in the 328.5 g of carbon dioxide produced when the hydrocarbon was burned in air.

1) Calculate the mass of carbon in 328.5 g of carbon dioxide:

Chemical formula of carbon dioxide: CO₂ Molar mass of CO₂: 12.011 g/mol + 2 * 15.999 g/mol = 44.009 g/mol Mass of C: x

x / 328.5 g CO₂ = 12.011 g C / 44.009 g/mol ⇒ x = 86.65 g C

2) Calculate the percent mass of carbon:

% = (mass of carbon / mass of carbon dioxide) * 100 =

= (89.65 / 112) * 100 = 80.04%

Round to three signifcant figures: 80.0%.