Question

Hydrogen gas is combined with oxygen gas to produce water. if you are given $25$ moles of oxygen, how many moles of hydrogen is needed

Answer 1

50 moles of hydrogen

Explanation:

In order to answer this question first you must formulate the balanced chemical equation that it gives us in the problem. So, using the information hydrogen gas is combined with oxygen gas we produced water we get the following equation.

$H_2+O_2\to 2H_{2}O$

Hydrogen gas and oxygen gas are both diatomic elements so they bind with themselves to form stable molecules. This is why they are $H_2$ and not H in the chemical equation.

Now we need to balance the equation.

$2H_2+O_2\to 2H_{2}O$

Using the above equation we can determine that for every 1 mole of oxygen 2 moles of hydrogen are required, giving us a 2:1 ratio. Using this ratio we can solve for the number of moles required for the reaction to take place.

$25mol{O}_2\left(\frac{2mol{H}_2}{1mol{O}_2}\right)=50mol{H}_2$