Purifying Water Flashcards

All 6 cards in this deck

What is potable water?

Water that is safe to drink. It may still contain impurities, as long as they are harmless.

Why is waste water filtered when making it potable?

To remove insoluble substances/solids, e.g. sand.

What is the reason for chlorination when making water potable?

To kill bacteria/microorganisms.

True or false? Water used in chemical analysis must not contain any dissolved salts.

True. Dissolved salts could interfere with or react in the analysis, giving incorrect results.

What happens in the sedimentation stage of water treatment?

The water is left to stand so insoluble particles sink to the bottom. A chemical such as aluminium sulfate can be added to make very small particles stick together into larger clumps, which settle faster.

Why is distilling sea water rarely used to make drinking water in the UK?

Boiling large volumes of water needs a lot of energy, so it is expensive. The UK has enough fresh water from rivers, lakes and ground water; distilling sea water is mainly used in dry countries with little fresh water.