Question

In a beaker there are 32.59g of salt dissolved in 400mL of water. On the bottom of the beaker there are 4.26g of salt sitting on the bottom, what is the percent mass of the solution? Record your answer in 3 sig figs.

Answer 1

To find the percent mass of the solution, the total mass of both dissolved and undissolved salt is divided by the total mass of the solution (water plus salt), and then multiplied by 100%. The calculated percent mass is 8.43%, rounded to three significant figures.

Step-by-step explanation:

To calculate the percent mass of the solution, we add the mass of dissolved salt to the mass of undissolved salt and then divide by the total mass of the solution (which is the sum of the mass of the water plus the mass of all the salt).

The mass of dissolved salt is 32.59g and the mass of undissolved salt is 4.26g. The total mass of the salt is then 32.59g + 4.26g = 36.85g.

Since we have 400mL of water and assuming the density of water is 1 g/mL, the mass of the water is 400g. Therefore, the total mass of the solution is 400g + 36.85g = 436.85g.

Now, we can calculate the percent mass of the solution:

Percent mass = (Total mass of salt / Total mass of solution) x 100%
Percent mass = (36.85g / 436.85g) x 100% = 8.43% (rounded to three significant figures)