Chemistry · May / June 2022 · Paper 61 · Question 4
0620
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The question as text
A sample of muddy river water contains water, dissolved solids and insoluble solid mud. Plan an investigation to find the concentration of dissolved solids, in g / dm3, in the river water. In your answer state how you will work out the concentration of the dissolved solids in g / dm3. You are provided with a small sample (less than 1 dm3) of muddy river water and common laboratory apparatus. (1 dm3 = 1000 cm3) [6]
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filter the water (1)
and any five from:
specified volume of water / filtrate
placed in a suitable container and heated in this container (evaporating basin / beaker)
heat/warm (to evaporate water)
(heat) until all water gone / to dryness / to constant mass
find mass of solid left
concentration = mass × 1000 ÷ volume used
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