Question

Determine how many grams of water are produced when burning 1.33 g of hexane, C6H14, as a component of gasoline in automobile engines. Assume excess oxygen is present

Answer 1

Combustion of hexane can be illustrated by the following reaction:
2C6H14 + 19O2 ...........> 12CO2 + 14H2O

From the periodic table:
mass of hydrogen = 1 gram
mass of oxygen = 16 grams
mass of carbon = 12 grams

Therefore:
molar mass of hexane = 6(12)+14(1) = 86 grams
mass of water = 2(1)+16 = 18 grams

From the balanced equation above:
2(86) = 172 grams of hexane produce 252 grams of water. To know the amount of water produced from 1.33 grams of hexane, all you have to do is cross multiplication as follows:
amount of water = (1.33x252) / 172 = 1.9486 grams