Question

How many moles of nitrogen gas are needed to react with 7.5 moles of hydrogen?

N2 + 3 H2 to 2 NH3

Answer 1

The balanced chemical equation for the reaction between nitrogen gas (
`N_2`) and hydrogen gas (
`H_2`) is:

`N_2 + 3H_2 \rightarrow 2NH_3`

According to the stoichiometry of the reaction, 1 mole of
`N_2` reacts with 3 moles of
`H_2` to produce 2 moles of
`NH_3`.

Therefore, to determine how many moles of
`N_2` are needed to react with 7.5 moles of
`H_2`, we need to use the mole ratio between
`N_2` and
`H_2`:

`\rm 1\: mole\: N_2 : 3\: moles\: H_2`

We can use this ratio to set up a proportion:

`\rm\frac{1\: \text{mol}\: N_2}{3\: \text{mol}\: H_2} = \frac{x\: \text{mol}\: N_2}{7.5\ \text{mol}\: H_2}`

Solving for x, we get:

`\rm{x = \frac{1\: \text{mol}\: N_2}{3\: \text{mol}\: H_2} \cdot 7.5\: \text{mol}\: H_2 = \boxed{2.5}\: \text{mol}\: N_2}`

`\therefore` 2.5 moles of
`N_2` are needed to react with 7.5 moles of
`H_2`.

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