Practice: A 5.12 L sample of solution contains 0.230 g of potassium sulfate, K_{2}SO_{4}. Determine the concentration of K_{2}SO_{4} in ppm if the density of the solution is 1.30 g/mL.

**Parts per Million (ppm)** and **Parts per Billion (ppb)** are used to express extremely dilute solution concentrations.

Concept #1: Parts per Million (ppm)

Example #1: What is the concentration in parts per million of DDT (nonbiodegradable pesticide) in 2.0 mg in 1.0 kg needlefish tissue?

Concept #2: Parts per Billion (ppb)

Example #2: A 2.4 L sample of an aqueous solution contains 0.012 mL of NH_{3}. What is the concentration of NH_{3} in the solution, expressed as parts per billion?

Practice: A 5.12 L sample of solution contains 0.230 g of potassium sulfate, K_{2}SO_{4}. Determine the concentration of K_{2}SO_{4} in ppm if the density of the solution is 1.30 g/mL.

Practice: Calculate the concentration in parts per billion of the following aqueous solution: 0.91 mg of caffeine in a total volume of 131 mL.

Practice: Glucose makes up about 0.102% by mass of human blood. Calculate this concentration in ppm.

Practice: The average human body contains about 5,000 grams of blood. What mass of arsenic is present in the body if the amount in blood is 0.86 ppb?

Practice: A water sample contains the pollutant chlorobenzene with a concentration of 16 ppm (by volume). What volume of this water contains 5.01×10^{2} mL of chlorobenzene?