Question

After 5 minutes, 1.98x10^-23 moles of hydrogen gas is produced. How many grams of magnesium reacted?

Answer 1

`\large \boxed{4.81 * 10^(-22) \text{ g Mg}}`

Step-by-step explanation:

We will need a balanced equation with masses, moles, and molar masses, so let’s gather all the information in one place.

Mᵣ: 24.30

Mg + 2H⁺ ⟶ Mg²⁺ + H₂

n/mol: 1.98 × 10⁻²³

1. Calculate the moles of Mg

The molar ratio is 1 mol Mg:1 mol H₂

`\rm \text{Moles of Mg} =1.98 * 10^(-23) \text{ mol H}_(2) * \frac{\text{1 mol Mg}}{\text{1 mol H}_(2)} = 1.98 * 10^(-23) \text{ mol Mg}`

2. Calculate the mass of Mg

`\text{Mass of Mg} = 1.98 * 10^(-23) \text{ mol Mg} * \frac{\text{24.30 g Mg}}{\text{1 mol Mg}} = \mathbf{4.81 * 10^(-22)} \textbf{ g Mg}\\\\\text{The mass of Mg reacted is $\large \boxed{\mathbf{4.81 * 10^{\mathbf{-22}} \textbf{ g Mg}}}$}`