Water purification
Test and purify a sample of water by distillation and chemical analysis
Check your understanding with these quick common questions. Use the drop down boxes to see the correct answers.
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In this practical you have to both describe how to test the sample for impurities or check its pH AND describe how to produce potable water. Remember, potable water is drinking water which contains some minerals. Distilled water just contains H2O.
This is a procedure, so you do not need to describe the variables. You do need to give details of equipment you will use.
It is possible you could have to compare types of water for impurities, in which case:
Independent: type of water (tap, river, sea, distilled).
Dependent: amount of dissolved solids / pH.
Control: same volume tested, same method, e.g. heating time if evaporating
Distillation apparatus, Bunsen burner, conductivity meter or pH probe.
Evaporating basin - a small dish that is heat proof.
Improve accuracy: Use a pan balance to measure the mass of dissolved solute. Use one with more decimals places.
Control validity: Ensure there is no contamination. Ensure when heating, the sample is heated until dry so no water is left behind.
Drinking (potable water) should have a pH near 7. It should not have high levels of salt.
To measure the mass of dissolved substances:
weigh container.
measure volume (100 cm3) of water into container.
evaporate / heat until dry.
weigh container and remaining solids.
determine mass of dissolved solids