A solution contains 15 ppm of benzene. The density of the solution is 1.00 g/mL. This means that ) A) there are 15 mg of benzene in 1.0 g of this solution B) 1.0 L of the solution contains 15 g of benzene C) the solution is 15% by mass of benzene D) 1.0 g of the solution contains 15 × 10^-⁶g of benzene E) 100 g of the solution contains 15 g of benzene

Question

Quizplus · Accepted Answer

Parts per million (ppm) is a unit of concentration. It represents the amount of solute (in this case, benzene) per million parts of solution. Therefore, 15 ppm means there are 15 parts of benzene per million parts of solution. Since the density of the solution is 1.00 g/mL, 1.0 g of the solution is equal to 1.0 mL. Therefore, 1.0 g of the solution contains the same amount of benzene as 1.0 mL of the solution.

To convert ppm to mg/g (milligrams per gram), we can use the following formula:

ppm = (mg of solute/g of solution) x 10^6

Rearranging this formula, we get:

mg of solute/g of solution = (ppm / 10^6)

Substituting the given values, we get:

mg of benzene/g of solution = (15 / 10^6)

= 0.015 mg/g

Therefore, 1.0 g of the solution contains:

mg of benzene = (0.015 mg/g) x 1.0 g

= 0.015 mg

Since there are 1000 mg in 1 g, we can convert this to 15 x 10^-6 g of benzene per 1 g of the solution. This can be simplified to 15 x 10^-6 g/g or 15 x 10^-6 g/mL. Therefore, the answer is D.

A Solution Contains 15 Ppm of Benzene