Chem 3.2

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What is the difference between soft and hard water?
Soft water lathers easily, hard water uses more soap and produces scum.
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What is the difference between scum and scale?
Scum is formed when soap reacts with compounds in ahrd water. Scale is the product of when temporary hard water is heated.
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Why is it better to drink hard water rather than soft water?
Hard water contains calcium compounds which are good for health, for the development of bones and teeth.
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What is meant by 'temporary hard water'?
Water that is softened by heating or boiling (and forms scale when its heated)
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How does an ion-exchanging resin soften hard water?
They remove the calcium and magnesium ions from hard water and replaces them (exchanges) for sodium or hydrogen ions.
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How is drinking water treated to make it safe to drink?
Sedimentation and filtration to remove solids and kill microbes, disinfecting using chlorine.
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Explain why distillation is not used to treat mains tap water.
It requires a large amount of energy so would be very expensive. Tap water does not need ot be pure to drink, just free from harmful substances.
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Suggest one advantage and one disadvantage of softening hard water.
Adv: uses less soap, doent produce scum, reduces the effect on heating sytems. Disad: reduces health benefits, costs money.
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What would be the consequences of not adding chlorine and fluoride to tap water?
No chlorine: increased health risks, more spreading of diseases. No fluride: more tooth decay, poor dental health.
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Other cards in this set

Card 2

Front

What is the difference between scum and scale?

Back

Scum is formed when soap reacts with compounds in ahrd water. Scale is the product of when temporary hard water is heated.

Card 3

Front

Why is it better to drink hard water rather than soft water?

Back

Preview of the front of card 3

Card 4

Front

What is meant by 'temporary hard water'?

Back

Preview of the front of card 4

Card 5

Front

How does an ion-exchanging resin soften hard water?

Back

Preview of the front of card 5
View more cards

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