Question

A solution is prepared by mixing .3355 moles of NaNO3 (84.995 g mol^-1) with 235.0 g of water (18.015 g mol^-1). Its density is 1.0733 g mL^-1. What is the percent by weight of NaNO3?

Answer 1

The percent by weight of NaNO3 in the solution is calculated by dividing the mass of NaNO3 by the total mass of the solution and then multiplying by 100%, resulting in a percent by weight of 10.82%.

Step-by-step explanation:

To calculate the percent by weight of NaNO3 in the solution, we first need to find the mass of NaNO3. Given the number of moles (0.3355 moles) and the molar mass of NaNO3 (84.995 g/mol), the mass of NaNO3 can be calculated as follows:

Mass of NaNO3 = Moles × Molar mass = 0.3355 moles × 84.995 g/mol = 28.511 g

Next, we add the mass of water (235.0 g) to the mass of NaNO3 to obtain the total mass of the solution.

Mass of solution = Mass of NaNO3 + Mass of water = 28.511 g + 235.0 g = 263.511 g

Lastly, the percent by weight of NaNO3 is:

Percent by weight = (Mass of NaNO3 / Mass of solution) × 100%
= (28.511 g / 263.511 g) × 100%
= 10.82%