To figure out how strong a solution is using mass percent, you need to know two things:

1. The weight of the solute (the substance you are dissolving).
2. The weight of the whole solution (solute plus solvent).

The formula to find mass percent looks like this:

Mass percent = (mass of solute / mass of solution) × 100

Let’s make this clearer with an example.

Imagine you dissolve 15 grams of salt in 85 grams of water.

To find the total weight of the solution, you add them together:

15 grams (salt) + 85 grams (water) = 100 grams (solution)

Now, let’s use the formula to find the mass percent of salt:

Mass percent of salt = (15 g / 100 g) × 100 = 15%

This tells us that the solution is 15% salt by weight!