Question

In this reaction, which mass of magnesium sulfate is formed when 6 g of magnesium react with excess sulfuric acid

Answer 1

To find the mole of H2 produced from 12g of Mg with an acid:

You can pick two acids; a dibasic and monobasic acid

Mg + 2HCl ------> MgCl2 + H2       (1 mole of hydrogen)

Mg + H2SO4----> MgSO4 + H2      (1 mole of hydrogen)

- in both instances the mole of hydrogen produced is 1 and the mole ratio of Mg:H2 is 1:1. This means that if there is 1 mole of Mg then there will be 1 mole of H2

Moles of 12g Mg:

Moles= mass

           molar mass

Molars mass magnesium = 24

moles = 12/24 = 0.5 moles.

since ratio was 1:1, then the moles of hydrogen produced will also be 0.5 moles

Therefore if 12g magnesium reacts with an acid half a mole of hydrogen gas is produced.