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21 Cards in this Set
- Front
- Back
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Carbonate hardness |
Also called temporary hardness is hardness caused by calcium and magnesium bicarbonate |
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Calcium and magnesium combined with carbonate (CO3) also contributes to ______- |
Total hardness |
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Nom carbonate hardness |
Also called permanent hardness is hardness caused by calcium and magnesium salts other than carbonate and bicarbonate salta |
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Hydrated lime |
Quicklime that has been combined with water. Also called slaked lime or calcium hydroxide |
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Recarbonation is |
The reintroduction of carbon dioxide into water following the softening process. This lowers pH |
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Slake definition |
The addition of water to quicklime to form calcium hydroxide which is used in the water softening and stabilization processes |
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Total hardness |
The combination of calcium and magnesium hardness. Also the combination of carbonate and non carbonate hardness |
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Ground water tends to be _______ than surface water |
Harder |
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61-120 mg/L as CaCO3 is considered what hardness |
Moderate |
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Target hard ness is considered |
50-85 mg/L as CaCO3 |
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We are mainly concerned with two forms of hardness |
Calcium hardness Magnesium Hardness |
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Total hardness = |
Calcium hardness + magnesium hardness |
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The 2 main objectives to water containing excessive hardness is |
Scale formation Calcium carbonate CaCO3 |
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Hardness reaction with soaps |
Ring around the tub Excessive soap use |
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Soft water problems |
Corrosive to plumbing |
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2 main types of precipitation chemicals are |
Lime softening Lime-soda ash softening |
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Lime or soda ash softening does what to pH in solids contact basin |
Brings it up. Normally to 11 |
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Carbon dioxide after lime softening does what to pH in recarbonation basin |
Brings pH down to around 8.6 |
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Mineral that cause non-carbonate calcium hardness are precipitated using |
Soda ash -Na2CO3 |
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Non carbonate magnesium hardness is precipitated using |
Lime - Ca(OH)2 |
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Unstable water is considered unstable it it either…. |
Deposits scale or is corrosive |
