What units are used for the concentration of chemicals in water?
When scientists measure compounds in a water sample, they usually express the results as a concentration – how much of the compound is found in a given volume (3-D space) of water? Three grams (3g) of sodium chloride salt dissolved in a Liter (1L) of water could be described as water with 3g/L of sodium chloride. In the same way you can double a recipe, this would be the same as having 6g of salt in 2L of water, but the results are usually reported per Liter or per milliliter (mL) so they can be compared easily. To picture a Liter, imagine an amount a little larger than a quart, or half of a 2L soda bottle. A milliliter (mL) is much smaller – exactly 1000mL makes 1L. A mL of water is about 20 drops. 1 mL of water has a mass of 1 gram (the metric system is set up that way on purpose). A gram is a little heavier than a paperclip. A gram is 1000 times heavier than a milligram. Follow this link for more on measurements from the National Insitute of Standards and Technology). Several of the
