# Solving Using PPM (Parts Per Million)

## Key Questions

• In order to calculate the parts per million you will need to know how many mg of solute is dissolved in 1000g (1L) of water.

$\frac{0.001 g}{1000 g}$ = 0.000001
Multiplying 0.000001 by 1,000,000 gives a result of 1ppm.

Here is a video discussing this type of calculation. In the video, the number of moles of barium present in a 1L sample of water with a barium concentration of 2ppm is calculated.

2 ppm is the maximum allowable level for barium in drinking water in the US as established by the EPA .

Video from: Noel Pauller

It's often used to measure contaminants, but there's other applications.

#### Explanation:

When you read about an article about air pollution or water pollution, you'll often see it refer to the concentration of contamination in ppm.

here's a NASA article talking about the concentration of CO2 in the atmosphere reaching 400ppm.

You can also get a water quality tester to see the concentration of foreign particles in the water.

• ppm is parts per million.

Just as a percentage is 1 part in 100 ppm is one part in a million. It's used to avoid very small numbers.

E.g a gas in the atmosphere could be 0.03%

To convert ppm you x by ${10}^{4}$ to give 300ppm.