Flashcards

Water

Alex C Chemistry GCSE English 9 cards

Cards in this deck (9)

1Water that lathers easily with soapsoft water
2How is scum formed?calcium/magnesium ions in hard water react with soap producing the insoluble solid
3How is scale formed?when temporary hard water is heated, insoluble magnesium/calcium carbonate is formed
reduces efficiency of heating systems
4How is water made safe to drink?Purified by filtration (removes solid) and by adding chlorine to kill bacteria
5How to test for hardnessuse equal amounts of water, add identical amounts of soap, shake and measure height of froth.
Higher froth= softer the water (proportional relationship)
6How do you soften temporary hard water?-when heated, hydrogencarbonate ions decompose to produce carbonate ions, water & CO2
-these carbonate ions react with magnesium/calcium ions in water, forming magnesium/calcium carbonate which are deposited as scale
7How to remove hardness in water using iron exchange columna) Use an ion exchange column packed with resin containing sodium ions
b) when hard water is passed through, Ca/Mg ions become attached to resin
and they are swapped for sodium ions
c) sodium ions don't react with the soap
8How to remove hardness in water by precipitating out ionsAdd Sodium Carbonate which causes the Ca/Mg ions to form calcium carbonate & magnesium carbonate precipitates (a solid that does not dissolve)
9Equation for softening of temporary hard water2HCO₃ (aq) ---> CO₃ (aq) + H₂O (l) + CO₂ (g)

Description: GCSE Chemistry (3) Further) Flashcards on Water, created by Alex C on 11/06/2016.
Created by: Alex C · Jun 2016
Updated: Jun 12, 2016
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