Question

For the reaction below, determine how many moles of hydrogen (H) are needed to react with0.344 moles of oxygen (O). Show all your work.2H2(g) + O2(g) → 2H2O(g)

Answer 1

0.688 moles of H.

Step-by-step explanation:

What is given?

moles of oxygen (O) = 0.344 moles.

molar mass of oxygen (O) = 16 g/mol.

molar mass of hydrogen (H) = 1 g/mol.

Chemical equation:

`2H_2+O_2\rightarrow2H_2O.`

Step-by-step solution:

In the statement, they're telling us that we have 0.344 moles of O, but since we have a compound of two oxygens as the reactant, then we have 0.688 (0.344 x 2 =0.688) moles of O2. So let's see how many moles of H2 we need to react with 0.688 moles of O2. You can see that 2 moles of H2 react with 1 mol of O2:

`0.688\text{ moles O}_2\cdot\frac{2\text{ moles H}_2}{1\text{ mol O}_2}=1.376\text{ moles H}_2.`

But the problem requires the number of moles of H, not H2, so we can divide the number of moles of H2 obtained by two:

`1.376\text{ moles H}_2\cdot\frac{1\text{ mol H}}{2\text{ moles H}_2}=0.688\text{ moles H.}`

The answer is that we need 0.688 moles of H to react with 0.344 moles of O.