Final answer:
The mass percent of NaNO3 in a 50.0g sample with 7.9g of NaNO3 is calculated using the formula (mass of solute / total mass of solution) × 100%, resulting in 15.8%.
Step-by-step explanation:
To calculate the mass percent of NaNO3 in a 50.0g sample where the mass of NaNO3 is 7.9g, use the following formula:
Mass percent = (mass of solute / total mass of solution) × 100%
In this case, the mass of the solute (NaNO3) is 7.9g, and the total mass of the sample (solution) is 50.0g.
Mass percent of NaNO3 = (7.9g / 50.0g) × 100%
Perform the division and then multiply by 100 to find the mass percent:
Mass percent of NaNO3 = 15.8%
The mass percent of NaNO3 in the 50.0g sample is 15.8%.