Question

Calculate the mass of hydrogen produced when 72 g of magnesium
reacts with sulfuric acid.

Answer 1

Since this is a single replacement reaction, the equation for the reaction is:

`\text{Mg}+\text{H}_(2)\text{SO}_(4) \longrightarrow \text{MgSO}_(4)+\text{H}_(2)`

From this, we know that for every mole of magnesium consumed, 1 mole of hydrogen is produced.

The atomic mass of magnesium is 24.305 g/mol, so 72 grams of magnesium is 72/24.305 = 2.9623534252211 moles.

This means we need to find the mass of 2.9623534252211 moles of hydrogen.

Hydrogen has an atomic mass of 1.00794 g/mol, so doubling this to get the formula mass of of
`\text{H}_(2)`, we get 2.01588 g/mol, which his a mass of:

(2.01588)(2.9623534252211). which is about 5.97 g