Question

Consider the reaction of magnesium metal with hydrochloric acid to produce magnesium chloride and hydrogen gas. If 3.29 mol of magnesium and 3.29 mol of hydrochloric acid are reacted, how many moles of excess reactant are left over?
a. 6.58 mol
b. 3.29 mol
c. 2.47 mol
d. 40.0 mol

Answer 1

Answer:

1.645 moles of excess reactant that is of magnesium metal are left over.

Explanation:

Moles of magnesium metal = 3.29 mol

Moles of HCl = 3.29 mol

$Mg(s)+2HCl(aq)\rightarrow MgCl_2(aq)+H_2(g)$

According to recation, 2 moles of HCl reacts with 1 mol of magnesium metal, then 3.29 moles of HCl will react with :

$\frac{1}{2}\times 3.29 mol=1.645 mol$ of magnesium metal

Moles of HCl left = 3.29mol - 3.29 mol = 0

Moles of magnesium metal left = 3.29 mol - 1.645 mol = 1.645 mol

1.645 moles of excess reactant that is of magnesium metal are left over.