When measuring very low concentrations of pollutants in water, which unit is most suitable?
- Molarity (mol L\(^{-1}\))
- Parts per million (ppm)
- Percentage by mass
- Volume percent (% v/v)
Aussie Maths & Science Teachers: Save your time with SmarterEd
When measuring very low concentrations of pollutants in water, which unit is most suitable?
\(B\)
→ Parts per million (ppm) is a unit used to express very low concentrations. One ppm means that there is 1 part of solute per 1,000,000 parts of solution. This unit is ideal for detecting small amounts of pollutants in large volumes of water, where concentrations are generally too low to be expressed effectively in molarity or percentage terms.
→ Molarity is a common unit for concentration but is better suited for more moderate to high concentrations in laboratory and industrial contexts, rather than for trace pollutants in water.
→ Percentage by mass and volume percent (% v/v) are typically used for relatively larger concentrations and are not as effective for expressing concentrations as low as parts per million.
\(\Rightarrow B\)