Question

Curious Carl and his lab partner were conducting a variety of experiments to produce gases: hydrogen, oxygen, and carbon dioxide. In one experiment, they added a piece of magnesium ribbon to 10 milliliters of hydrochloric acid. They observed bubbles being produced and did a variety of tests to identify the escaping gas; it proved to be hydrogen. The reaction is represented by the following equation:
Mg + 2HCl → MgCl2 + H2(g)

What is the mass, in grams, of two moles of HCl?
A) 18.3 g
B) 36.5 g
C) 72.0 g
D) 73.0 g

Answer 1

Given:
Balanced Chemical Equation:

Mg + 2HCl --> MgCl2 + H2

Volume of HCl = 10 mL
Molar mass of HCl = 36.46 g/mol

The mass, in grams, of two moles HCl is:

2 moles * 36.46 g/mol = 72.92 grams or 73.0 g (letter D)

Answer 2

Answer:

73.0 grams is the mass of two moles of HCl.

Explanation:

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

Moles of HCl = 2 moles

Molar mass of HCl = 36.5 g/mol

$n=\frac{m}{M}$

n = number of moles

m = Mass of the given compound

M = molar mass of the compound

$2 mol=\frac{m}{36.5 g/mol}$

m = $2mol\times 36.5 g/mol=73.0 g$

73.0 grams is the mass of two moles of HCl.