Question

Find the number of moles of water that can be formed if you have 126 mol of hydrogen gas and 58 mol of oxygen gas.

Answer 1

Answer : The number of moles of water formed can be 116 moles.

Explanation :

First we have to calculate the limiting and excess reagent.

The balanced chemical reaction will be:

$2H_2+O_2\rightarrow 2H_2O$

From the balanced chemical reaction we conclude that,

As, 1 mole of $O_2$ react with 2 mole of $H_2$

So, 58 moles of $O_2$ react with $58\times 2=116$ moles of $H_2$

From this we conclude that, $H_2$ is an excess reagent because the given moles are greater than the required moles and $O_2$ is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of $H_2O$

From the reaction, we conclude that

As, 1 mole of $O_2$ react to give 2 mole of $H_2O$

So, 58 moles of $O_2$ react to give $58\times 2=116$ moles of $H_2O$

Therefore, the number of moles of water formed can be 116 moles.

Answer 2

Since a water molecule is H2O, you would divide 126 hydrogen molecules by 2, and you would get 63. That means you have 63 double hydrogen molecules, and 58 oxygen molecules to pair up with them. So that means you could have 58 molecules of water, with 5 double hydrogen molecules, so basically 10 extra molecules of hydrogen along with the H2O molecules. Hope I helped! :)