Understanding Parts Per Million (ppm) in Chemistry

What type of concentration is calculated when the grams of solute is divided by the grams of the solution and the result is multiplied by 1,000,000?

(1) molarity

(2) parts per million

(3) percent by mass

(4) percent by volume

Answer:

The correct answer is option 2 - parts per million (ppm).

Parts per million (ppm) is a unit of concentration that represents the number of grams of solute per 1,000,000 grams of solution. It is commonly used to express the concentration of very dilute solutions.

For example, if there are 500 grams of solute in a solution that has a total mass of 1,000,000 grams, the concentration would be 500 ppm.