Flashcards
Hard and Soft water
Cards in this deck (23)
- 1what does hard water produce?scum and scale
- 2how do you know if water is hard or not?if it is hard then it will take more soap to produce a lather
- 3what ions affect water hardness?magnesium mg2+ and calcium ca2+ and it will depend on which compound they're in
- 4which type of hardness is soluble in water?permanent hardness
- 5what compounds will make water permanantly hard?sulphate and chloride compounds
- 6what compounds are made by permanent hardness?magnesium sulphate mgso4
calcium sulphate caso4
magnesium chloride mgcl2
calcium chloride cacl2 - 7what is gypsum?calcium sulafate caso4
-a rock found in rivers that turns soft water into hard water - 8what 2 ways can remove permanent hardness?An ion exchange column and washing soda,Na2CO3.
- 9how does an ion exchange column work?mg2+ and ca2+ are replaced by sodium ions, which turns water soft.
- 10how does washing soda remove permanent hardness?the carbonate, Na2CO3, joins to the calcium ions to make an insoluble precipitate of calcium carbonate, CaCO3, which is limestone and this can then be removed, laving just sodium, (soft water).
- 11what is temporary hardness caused by?carbonate compounds
- 12is temporary hardness soluble or insoluble in water?insoluble in water
- 13example of a temporary hardness compound?calcium carbonate CaCO3, limestone.
- 14how is temporary hardness formed?calcium carbonate reacts with carbonic acid (acid rain) to form calcium hydrogencarbonate.
- 15how is carbonic acid formed?when carbon dioxide and water react.
- 16symbol equation for making acid rain?CO2+H2O=H2CO3
- 17word equation for making carbonic acid?carbon dioxide+water=carbonic acid (acid rain).
- 18is carbonic acid insoluble in water?nope, it's soluble.
- 19is the formation of calcium hydrogencarbonate an irreversible or reversible reaction?reversible reaction.
- 20how does calcium hydrogencarbonate turn back into carbonic acid and calcium carbonate?by boiling
- 21word equation for forming calcium hydrogencarbonatecarbonic acid+calcium carbonate ^v calcium hydrogencarbonate
- 22symbol equation for forming calcium hydrogencarbonate... use ^v for reversible reaction symbol.H2CO3+CaCO3 ^v Ca(HCO3)2
- 23How can temporary hardness be removed? (3 ways).by boiling/ ion exchange column/ washing soda, Na2CO3
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- Flashcards on Hard and Soft water, created by Nora Okeke on 18/06/2016.
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- Nora Okeke
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- Created by abbie Fitzpatrick · Jan 28, 2015
- Copied by Nora Okeke · Jun 18, 2016
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