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 molar mass of MgCl2?
A. 35.45g
B. 95.21g
C. 59.76g
D. 24.31g

1 answer

C. 95.21g

To calculate the molar mass of MgCl2, we need to add up the atomic masses of magnesium (Mg) and chlorine (Cl).

The molar mass of magnesium (Mg) is 24.31 g/mol and there are two chlorine atoms in magnesium chloride (MgCl2), so we need to multiply the atomic mass of chlorine (35.45 g/mol) by 2.

Mg: 1 x 24.31 = 24.31 g/mol
Cl: 2 x 35.45 = 70.90 g/mol

Adding these together, we get:
24.31 g/mol + 70.90 g/mol = 95.21 g/mol

Therefore, the molar mass of MgCl2 is 95.21 g/mol.