Hard water

1

What ions cause hardness in water?

2

Which method can be used to remove temporary hardness but not permanent hardness from a sample of water?

3

What dissolved compound is responsible for causing temporary hardness in water?

4

A sample of tap water is tested for hardness. It is found that 23 cm3 of soap solution is needed to form a long-lasting lather. A sample of the same tap water is boiled, allowed to cool and then tested for hardness. The boiled sample required 17 cm3 of soap solution to form a long-lasting lather. What conclusion can be drawn about the type of hardness in this tap water?

5

Which statement correctly describes the method for determining the hardness of water?

6

Which of the following is a benefit of hard water?

7

Which water sample contains temporary hard water?

3 column table labelled Water sample, (A, B and C) and Volume of soap solution needed in cm cubed Before boliing and After boiling. The figures are A: 11.5 & 11.5, B: 2.5 & 2.5, C: 7.0 & 2.5.

8

What is the mean volume of soap added for sample B?

6 column table. Column 1 is labelled Sample. Columns 2-6 are labelled Volume of soap solution added in cm cubed and further divided into Test 1-4 and Mean. Figures for Row B are 11, 18, 12, and 13.

9

What can be used to identify whether a sample of water is hard or soft?

10

Which equation represents the symbol equation for the removal of temporary hardness from water?