Which negative ion has the greatest concentration, in $\text{g dm}^{-3}$, in this water sample?
State the name of the ion with formula $\text{SO}_4^{2-}$.
Calculate the mass of sodium ions present in $1\,\text{dm}^3$ of this river water.
Describe a test for nitrate ions, and give the test result.
What method could be used to remove insoluble materials from river water?
From the following, which two substances are components of food? Tick two boxes: alkane, carbohydrate, graphite, protein.
Clay particles suspended in river water exhibit Brownian motion. Describe how these particles move.
Explain why farmers make use of fertilisers.
Explain why adding calcium hydroxide to the soil at the same time as nitrate fertilisers leads to nitrogen being lost from the soil.