Question

A student is collecting the gas produced from the reaction of 1.5 grams of Mg with excess HCl. When the reaction is complete, how many moles of H2 should have been produced?

A. 1.5 moles
B. 0.75 moles
C. 0.062 moles

Answer 1

The number of moles of H2 produced when 1.5 grams of Mg reacts with excess HCl is 0.062 moles. Option C

Step-by-step explanation:

The balanced chemical equation for the reaction between magnesium (Mg) and hydrochloric acid (HCl) is:

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

From the equation, we can see that for every 1 mole of magnesium reacted, 1 mole of hydrogen gas (H2) is produced. Therefore, the number of moles of H2 produced is equal to the number of moles of Mg reacted.

In this case, 1.5 grams of Mg was reacted. To find the number of moles of Mg, we can use its molar mass, which is 24.305 g/mol.

Number of moles of Mg = mass of Mg / molar mass of Mg = 1.5 g / 24.305 g/mol = 0.0617 mol

Therefore, the correct answer is C. 0.062 moles.