What is the mass by mass percentage of salt in a solution prepared by dissolving 10 g of salt in 90 g of water?

The correct option is 10%.

Step-by-Step Explanation:

1. Identify the given values:

Mass of the solute (salt) = 10 g

Mass of the solvent (water) = 90 g

2. Calculate the total mass of the solution:

The total mass of the solution is the sum of the mass of the solute and the mass of the solvent.

$\text{Mass of solution}=\text{Mass of solute}+\text{Mass of solvent}$

$\text{Mass of solution}=10\text{ g}+90\text{ g}=100\text{ g}$

3. Use the formula for mass by mass percentage:

The mass percentage of a solute in a solution is given by the formula:

$\text{Mass percentage}=\left(\frac{\text{Mass of solute}}{\text{Mass of solution}}\right)\times 100$

4. Substitute the values into the formula:

$\text{Mass percentage}=\left(\frac{10}{100}\right)\times 100=10\%$

Hence, the mass by mass percentage of salt in the solution is 10%.