Question

calculate the amount of water produced by the combustion of 32g of methane

Answer 1

16 G METHANE PRODUCES 36 G H20

32 G METHANE PRODUCES 72 G H20

Answer 2

Answer: 72 grams of water will be produced.

Explanation: Combustion reaction is a type of reaction in which hydrocarbon is decomposed in the presence of air to form carbon dioxide and water.

Reaction for combustion of methane is written as:

$CH_4(g)+O_2(g)\rightarrow CO_2(g)+H_2O(l)$

As combustion is done in the presence of air, hence oxygen gas is present in excess and is therefore, considered as excess reagent.

Methane is considered as the limiting reagent because it limits the formation of product.

Moles can be calculated by:

$Moles=\frac{\text{given mass}}{\text{Molar mass}}$    ....(1)

Molar mass of methane = 16 g/mol

$\text{moles of }CH_4=\frac{32g}{16g/mol}=2moles$

By stoichiometry,

1 mole of methane produces 2 moles of water

Hence, 2 moles of methane will produce = $\frac{2}{1}\times 2=4moles$

Water produced = 4 moles,

Amount of water can be calculated by using equation 1, we get

Molar mass of water = 18 g/mol

$4moles=\frac{\text{amount of water}}{18g/mol}$

Amount of water produced = 72 grams.