Question

Given this reaction: `CH_4 + 2O_2 -> CO_2 + H_2O`, 16 g of `CH_4` react with 64 g of `O_2`, producing 44 g of `CO_2`. How many grams of water are produced?

Answer 1

`36` grams of water will get formed.

Explanation:

There are actually two methods of doing it - stoichimetry & also with the help of law of conservation of mass.

First by stoichiometry:

`16`grams of `CH_4` means `1`mole of it.

Now, after balancing the entire equation we get:

`CH_4+2O_2 rarr CO_2+2H_2O`.

So, 1 mole of methane produces 2 moles of water. Hence, `36` grams of water is formed.

Now by law of conservation of mass:

The entire mass of the reactants will be equal to the entire mass of the products after the reaction.

So, mass of water formed `=(16+64)-44` grams, i.e. `36` grams.