Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
13 Cards in this Set
- Front
- Back
|
How does hard water form?
|
When calcium reacts with magnesium.
|
|
|
What forms when soap is added to water?
|
Lather (Suds)
|
|
|
What does temporary hard water contain?
|
Dissolved calcium hydrogen-carbonate
|
|
|
What does permanent hard water contain?
|
Dissolved calcium sulphate
|
|
|
What is scum?
|
Scum is formed when calcium and magnesium ions react with soap. |
|
|
What is scale?
|
A substance formed when heart water is boiled and there compounds decompose. |
|
|
Give 2 ways how permanent hard water can be softened? |
1) Adding sodium carbonate to water 2)Using ion exchange columns |
|
|
What is lime scale and how is it formed?
|
Lime scale is a chalky substance often fount on heating elements and is formed by insoluble calcium carbonate. |
|
|
Name the two key steps to the purification of water |
1) Filter the water 2)Chlorinate the water |
|
|
Name two substances added to water
|
1) Chlorine 2) Fluoride |
|
|
What do water filters contain?
|
1) Silver to kill bacteria 2). Carbon to absorb impurities 3). Ion exchange resins to soften water |
|
|
Advantages of hard water |
1) People prefer the taste 2) calcium ions are good for bones and teeth |
|
|
Disadvantages of hard water |
1) Scum may form 2) Difficult to form lather with soap |
