Flashcards
Hard Water
Cards in this deck (8)
- 1What do you get with hard water and soap?Scum- the dissolved calcium & magnesium ions in the water react with soap to form scum
- 2What causes temporary hardwater?1. Rain water is naturally weakly acidic because it contains carbonic acid- carbon dioxide and water react in the atmosphere
2. When the rain falls, it flows over rocks and compounds, it dissolves these compounds and magnesium and calcium ions can get into the water - 3Carbonic acid + Calcium carbonate =?Calcium Hydrogencarbonate
- 4What is hard water good for?Teeth and bones, less risk of heart disease
- 5How can we soften hard water?1. Heating
2. Adding washing powder
3. Ion exchange columns - 6What happens when you heat TEMPORARY hard water?Temporary hardness can be removed by boiling. When heated, the calcium hydrogen carbonate decomposes to form calcium carbonate which is insoluble. This is scale.
- 7How does adding washing powder to hard water work?BOTH TYPES OF HARDNESS an be softened by adding washing soda (SODIUM CARBONATE) to it. The added CARBONATE IONS react with calcium and magnesium ions to make an INSOLUBLE PRECIPITATE of calcium carbonate and magnesium carbonate. The calcium & magnesium ions are no longer dissolved in the water- not hard water
- 8How does an ion exchange column work?BOTH TYPES OF HARDNESS can be removed by running water through ion exchange columns. The columns have lots of SODIUM OR HYDROGEN IONS and 'exchange' them for calcium or magnesium ions in the water than runs through them
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- GCSE Chemistry - C3 Flashcards on Hard Water, created by Gretta Mildred on 13/05/2015.
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- Gretta Mildred
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