Question

a. The compound ${\mathrm{MgSO}}_4$, Epsom salts, is used to soothe sore feet and muscles. How many grams will you need to prepare a bath containing localid="1653460710134" $5.00$mole of Epsom salts?

b. Potassium iodide, $\mathrm{KI}$, is used as an expectorant. How many grams are inlocalid="1653460784056" $0.450$moleof potassium iodide?

Short answer

(a) The $602$g is needed to prepare a bath containing $5.00$moleof Epsom salts

(b) The $74.7$g are in $0.450$mole of potassium iodide

Step-by-step solution

Part (a) Step 1: Given information

We need to find the amount needed to prepare a bath containing $5.00$mole of Epsom salts

Part (a) Step 2: Simplify

We know that

A mole is equal to molar mass

And molar mass of Epsom salt is, $120.38\mathrm{g}/\mathrm{mol}$

Therefore, the amount needed to prepare a bath containing$5.00$mole of Epsom salts is, localid="1653481987514" $120.38\frac{\mathrm{g}}{\cancel{\mathrm{mol}}}\times 5\cancel{\mathrm{mol}}=602\mathrm{g}$

Part (b) Step 1: Given information 

We need to find the mass in $0.450$moleof potassium iodide

Part (b) Step 2: Simplify 

We know that

A mole is equal to molar mass

And molar mass of potassium iodide is, $166$g

Therefore, the mass in $0.450$moleof potassium iodide is,$166\frac{\mathrm{g}}{\cancel{\mathrm{mol}}}\times 0.45\cancel{\mathrm{mol}}=74.7\mathrm{g}$