Hard water: temporary and permanent hardness

Hard Water

• 
• - Calcium ions and magnesium ions make the water hard.
• - Hard water makes it difficult to form a lather unlike soft water.
• - Hard water makes scum, showing that more soap is needed
• - Glasses will have residue on them
• Bildunterschrift: Difference between hard and soft water

Temporary vs. permanent hard water

• Temporary:
• - Temporary hard water contains magnesium/calcium hydrogen carbonates
• - When heated the hardness is removed BUT it forms calcium carbonate (scale) which clogs up pipes
• -Temporary hard water is caused by dissolved calcium hydrocarbonates
• Permanent:
• - Permanent hard water can not be softened when boiled
• - It is caused by a very soluble magnesium sulfate and a slightly soluble calcium sulfate.
• - In order to soften it, you must remove the magnesium ions or the calcium ions (As you'll see in the next slide)

Conventional water sofetning

• 
• - Most conventional water softnening devices tend to need to exchange the calcium ions with sodium and chloride ions... that are loosly bound to an ion exchange resin or a zeolite
• -Many zeolite minerals occur by nature but specialised ones are made artificially
• Bildunterschrift: Calcium being exchange by sodium and chloride ions

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