Question

A student is collecting the gas produced

from the reaction of 1.5 grams of Mg with

excess HCI. When the reaction is

complete, how many moles of H2 should

have been produced?

Answer 1

0.062 moles of hydrogen gas

Step-by-step explanation:

We must first out down the reaction equation before we can attempt to solve the problem.

Mg(s) + 2HCl(aq) ----> MgCl2(aq) + H2(g)

Next we obtain the number of moles in 1.5 g of magnesium metal from;

Molar mass of magnesium = 24.3 gmol-1

Number of moles of magnesium= mass/molar mass = 1.5g/24.3gmol-1 = 0.062 moles

From the reaction equation;

1 mole of magnesium metal yields 1 mole of hydrogen gas

0.062 moles of magnesium metal will yield 0.062 moles of hydrogen gas

Therefore, reaction of 1.5g of magnesium metal with excess hydrochloric acid will yield 0.062 moles of hydrogen gas.