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Investigating the Hardness of Water

Satisfactory Essays
Investigating the Hardness of Water

Planning

Aim

To investigate the hardness of water in 5 different water solutions

Background knowledge about hard water

The hardness of water is caused by the presence of Calcium 2+ and

magnesium 2+ ions in the water. These minerals in water can cause some

everyday problems. They react with soap and produce a deposit called

"soap scum" that remains on the skin and clothes and, because it is

insoluble and sticky, cannot be removed by rinsing. Soap curd changes

the pH of the skin and may cause infection and irritation. It also

remains on the hair making it dull and difficult to manage. Soap scum

picks up the dirt from laundry water and holds it on cloth,

contributing to a grey appearance of white clothes. It is especially

troublesome when wash water is allowed to drain through the clothes.

The use of synthetic detergents may help a little, but the active

ingredient in the detergent is partially inactivated by hardness and

more detergent must be used for the same cleaning task. Some

detergents will produce soap during the reaction with oil or grease on

the surface being cleaned and as a result they will also deposit soap

curd. A ring around the bathtub and spotting on glassware, chrome, and

sinks are constant problems in the presence of hard water. They

require additional rinsing and wiping, increasing the time spent on

everyday cleaning.

Cooking with hard water can also be difficult, producing scale on

pots. Some vegetables cooked in hard water lose colour and flavour.

Beans and peas become tough and shrivelled. Hard water may also

shorten the life of plumbing and water heaters. When water containing

calcium carbonate is heated, a hard scale is formed that can plug

pipes and coat heating elements. Scale is also a poor heat conductor.

With increased deposits on the unit, heat is not transmitted to the

water fast enough and overheating of the metal causes failure.

Build-up of deposits will also reduce the efficiency of the heating
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