Hydrogen gas can be produced by the reaction of magnesium metal with hydrochloric acid by the reaction below.

Question

Mg + 2HCl → MgCl2 + H2
How many grams of magnesium chloride is produced in the reaction?

4.18 g MgClmc003-1.jpg

8.34 g MgClmc003-2.jpg

15.7 g MgClmc003-3.jpg

95.2 g MgClmc003-4.jpg

Answer 1

To determine the mass of magnesium chloride produced in the reaction, we need to first calculate the molar mass of MgCl2.

The molar mass of MgCl2 can be calculated by adding the atomic masses of each element:

Mg: 24.31 g/mol
Cl: 35.45 g/mol (there are 2 Cl atoms in MgCl2)

Molar mass of MgCl2 = 24.31 g/mol + (35.45 g/mol x 2) = 95.21 g/mol

Using stoichiometry, we can determine the mass of MgCl2 produced from the given mass of Mg:

1 mole of Mg produces 1 mole of MgCl2 (according to the balanced equation)

Thus, the mass of MgCl2 produced = (mass of Mg) x (molar mass of MgCl2) / (molar mass of Mg)

= (4.18 g)(95.21 g/mol) / ( 24.31 g/mol)

= 16.4 g MgCl2

Therefore, the correct answer is 15.7 g MgCl2.