Required Practicals - Water Purification Flashcards
What is the goal of the water purification practical?
To analyse and purify a sample of water, to make it safe to drink.
What is the apparatus of the water analysation practical?
-10cm3 of each water sample to be tested.
-Universal indicator paper or solution.
What is the method of the analysing water practical?
-Use the universal indicator paper to measure the pH of the sample.
-Accurately weigh an empty evaporating basin and record to 2dp.
-Pour 10cm3 of water sample 1 into the evaporating basin.
-Heat the evaporating basin using a bunsen burner until the solids form and the majority of water has evaporated.
-Weigh the cooled evaporating basin again and calculate the mass of the solids that were dissolved in the water.
-Record the results in a table.
What is the apparatus for the water purification practical?
-10cm3 of water sample 1
-Bunsen burner
-tripod
-gauze
-heatproof mat
-clamp and clamp stand
-conical flask with delivery tube and bung
-boiling tube
-ice bath
What is the method for the water purification practical?
-Place the water sample in the conical flask.
-Heat the water using the bunsen burner until it boils. Then reduce the heat so that the water boils gently.
-The distilled water will collect in the cooled test tube. Collect about 1cm depth of water in this way, then stop heating.
-Analyse the water you have distilled by determining its boiling point.
What is the difference between potable and pure water?
Potable water is drinkable but still contains microbes and some non-harmful bacteria but pure water contains only H2O molecules and no useful bacteria.
What is potable water?
Water that is safe to drink
Is potable water the same as pure water?
Why?
It isn’t as potable water contains useful ions, pure water does not as it only has H2O molecules
What pH does pure water have?
pH 7
What is the aim of the water practical?
To test if it is pure water or not
How can we check the pH of water?
By adding universal indicator paper to the sample of water.
Which colour is universal indicator paper if the sample is pH 7?
Green
Why would a water sample not have a pH of 7?
If it contains dissolved acids or alkalis.
This would necessitate that it isn’t pure.
Why does a water with pH 7 not guarantee that it is pure?
It may have dissolved solids that do not affect acidity of the water
How do we test if there are dissolved solids in a water sample?
Use a balance to weigh an empty evaporating basin and record the mass.
Fill the basin with the water sample and place it on a tripod and gauze.
Use a bunsen burner to gently heat the water until it all evaporates.
Allow the evaporating basin to cool and weigh it again.
If the water contained any dissolved solids, the mass will have increased.
