Question

A solution is made by dissolving 4.87 g of potassium nitrate in water to a final volume of 86.4 mL solution. What is the weight/weight % or percent by mass of the solute?
Answer is 5.63

Answer 1

Answer:

The weight/weight % or percent by mass of the solute is 1.04g.mL

Explanation:

We assume, (i) that the solvent is water, and (ii) that dissolution occurs without change in volume.

So given the standard density of water, the mass of the solution is simply,

(4.87+86.4)g

For solution, $\frac{mass}{volume}=density$

                                = $\frac{4.87+86.4g}{86.4mL}$

                                = 1.04 g. mL

Because nitrate salts are soluble stuff, you could get significantly higher solution densities if you dissolved more salt (volume change would be fairly negligible).