Hardness of water Flashcards
What does hard water make?
- Scum.
- Scale.
What do you get with soft water and soap?
A nice lather (bubbles) with soap.
What do you get with hard water and soap?
Scum, which is insoluble (unless your using a soap less detergent).
Why does soap and hard water react to make scum?
Dissolved calcium ions and magnesium ions in the water.
Using hard water how do you get a decent lather?
By using more soap (which isn’t free).
What does using more soap with hard water mean?
More money is wasted.
What happens when you heat hard water?
Furring or scale is formed on the insides of pipes, boilers and kettles.
What do badly scales up pipes and boilers reduce?
The efficiency of heating systems, so they meat need to be replaced (which costs money).
What does scale eventually do?
Block pipes.
What is scale also?
A bit of a thermal insulator.
What does scale being a bit of a thermal insulator mean?
That kettles with scale on the heating element take longer to boil than a non-scaled up kettle, meaning it becomes less efficient.
What is hardness of water caused by?
Because it contains lots of calcium and magnesium ions.
How does hard water get calcium and magnesium ions?
When rain falls on some types of rocks (e.g. Limestone, chalk and gypsum) they can dissolve compounds like magnesium sulfate (soluble) and calcium sulfate (a little bit soluble).
Why isn’t hard water all bad?
Because Ca^2+ ions are good for healthy teeth and bones.
What have studies found showing that hard water isn’t all bad?
That people who live in hard water areas are at less risk of developing heart disease than those in soft water areas (possibly because of the minerals in hard water).
