Question

Magnesium chloride, MgCl2, is an important industrial chemical.

Answer 1

This problem is providing information about a reaction between magnesium and hydrochloric acid. However, the moles of the latter are required given 50 cm³ of a 0.2-M solution, making this problem more about the application of molarity. At the end, the answer turns out to be 0.01 mol.

Molarity:

In chemistry, we use units of concentration in order to represent the relative amounts of solute and solvent in a solution. More specifically, molarity relates the moles of the solute with the liters of solution according to:

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

Thus, since this problem asks for the moles of hydrochloric acid in 50 cm³ of a 0.2-M solution, we must first calculate the volume in liters with:

$V=50cm^3*\frac{1L}{1000cm^3} =0.050L$

To finally solve for n, moles, to obtain:

$0.2mol/L=\frac{n}{0.05L} \\\\n=0.2mol/L*0.05L\\\\n=0.01mol$

Learn more about molarity: brainly.com/question/9468209