CHEMISTRY HELP PLEASE

Question

How many liters of hydrogen gas at STP can be generated from the reaction of excess hydrogen chloride with 67.3 g of aluminum?

Answer 1

First, write the correctly balanced equation:

6HCl + 2Al ==> 2AlCl₃ + 3H₂ ... balanced equation

Recall that at STP, one mole of any ideal gas occupies 22.4 liters.

Convert g Al to moles Al:

67.3 g Al x 1 mol Al / 26.98 g = 2.494 moles Al

Since HCl is in excess, we can find moles H₂ formed from 2.494 moles of Al:

2.494 moles Al x 3 moles H₂ / 2 moles Al = 2.494 moles H₂

Using 22.4 L/mol, we can now convert this to liters of H₂:

2.494 moles H₂ x 22.4 L/mole = 55.9 L (3 sig. figs.)