An early method of producing hydrogen gas was passing steam through red-hot iron pipes according to the reaction

3 Fe (s) + 4 H2O (g) → Fe3O4 (g) + 4 H2 (g)

How many liters of hydrogen gas at STP can be created by reacting 15.3 g of iron?

Answer;

= 8.1536 Liters

Explanation;

Moles = mass/R. A. M

Moles of Iron = 15.3 g / 56 g/mol

= 0.273 moles

For every three moles of Iron used, 4 moles of Hydrogen are produced.

Therefore;

Moles of Hydrogen = (0.273/3) * 4

= 0.364 moles

But 1 mole of a gas occupies 22.4 liters at STP

Thus;

Volume of Hydrogen = 0.364 * 22.4 l

= 8.1536 Liters