Question

If 156 g of magnesium are recovered from the decomposition of 1094.6 g of magnesium chloride, what is the theoretical yield?

Answer 1

The theoretical yield is 279 g, the actual yield is 55.8 %.

Step-by-step explanation:

Hi!

The molar mass of magnesium chloride (MgCl₂) is 95.211 g/mol (it is calculated as the molar mass of Mg + 2 × the molar mass of Cl). That means that 1 mol of Mg is present in 95.211 g of MgCl₂

Then, in 1094.6 g of MgCl₂ there will be:

(1094.6 g MgCl₂ · (1 mol Mg /95.211 g of MgCl)) 11.497 mol Mg.

In grams: 11.497 mol Mg · ( 24.305 g Mg / 1 mol) = 279.43 g

This is the amount that would be obtained theoretically in the decomposition of magnesium chloride.

But we obtained 156 g Mg, so let´s find the actual yield of the rection:

If 279.43 g Mg would represent a 100% yield, 156 g Mg will be:

156 g Mg · (100% / 279.43 g Mg) = 55.8%