Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!

Water is a solvent - this means substances in it.
Certain dissolved substances prevent it from forming a lather - this is called .
Hardness can be detected using a test.
The dissolved compounds causing hardness are compounds of .
Hardness can be removed using an exchanger.
To obtain a sample of water from sea-water, a simple could be carried out.
Water can be de-composed using a process called .
This releases the gases and .