Question 1
Question
True or false? Using hard water makes it more difficult for soap to lather.
Question 2
Question
Which of these rocks helps to cause hardness in water?
Answer
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Gypsum
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Granite
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Dolomite
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Calcite
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Basalt
Question 3
Question
Which type of deposit forms when hard water reacts with soap?
Answer
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Scale, calcium carbonate
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Scum, calcium stearate
Question 4
Question
Which type of deposit forms when hard water is boiled?
Answer
-
Scale, calcium carbonate
-
Scum, calcium stearate
Question 5
Question
True or false? Calcium carbonate dissolves in carbonic acid (rainwater) to produce calcium ions and hydrogencarbonate ions.
Question 6
Question
Which type of hard water can be softened by heating?
Answer
-
Permanent hard water
-
Temporary hard water
Question 7
Question
True or false? Scale is formed upon heating temporary hard water because calcium hydrogencarbonate forms a precipitate.
Question 8
Question
Which of these methods can soften either type of hard water?
Answer
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Washing soda
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Boiling
-
Ion-exchange column
Question 9
Question
Which ion is exchanged with calcium and magnesium ions in an ion-exchange column?
Answer
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Potassium K+
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Sodium Na+
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Cadmium Cd2+
-
Iron Fe3+
Question 10
Question
True or false? Ion-exchange columns do not need to be regularly washed out with saline solution.
Question 11
Question
What is the first stage in the water treatment process?
Answer
-
Passing water through a sand filter for clear water
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Passing water through metal meshes to remove large objects
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Chlorination of water to kill bacteria
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Adding aluminium sulphate and lime to encourage flocculation of suspended particles in the water
Question 12
Question
What is the second stage in the water treatment process?
Answer
-
Passing water through a sand filter for clear water
-
Passing water through metal meshes to remove large objects
-
Chlorination of water to kill bacteria
-
Adding aluminium sulphate and lime to encourage flocculation of suspended particles in the water
Question 13
Question
What is the third stage in the water treatment process?
Answer
-
Passing water through a sand filter for clear water
-
Passing water through metal meshes to remove large objects
-
Chlorination of water to kill bacteria
-
Adding aluminium sulphate and lime to encourage flocculation of suspended particles in the water
Question 14
Question
What is the fourth stage in the water treatment process?
Answer
-
Passing water through a sand filter for clear water
-
Passing water through metal meshes to remove large objects
-
Chlorination of water to kill bacteria
-
Adding aluminium sulphate and lime to encourage flocculation of suspended particles in the water
Question 15
Question
What is often contained in a filter cartridge?
Answer
-
Activated carbon
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Activated boron
-
Ion-exchange column
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Fractionating column
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Silver
-
Ruthenium
Question 16
Question
What are health benefits of drinking hard water?
Question 17
Question
Which gas is sometimes used as an alternative to chlorine in killing bacteria?
Answer
-
Fluorine
-
Hydrogen sulphide
-
Ozone
-
Methane
Question 18
Question
Which ion is sometimes added to water to reduce the risk of tooth decay?
Answer
-
Sulphate, SO42-
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Fluoride, F-
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Nitrate, NO3-
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Potassium, K+
Question 19
Question
Which of these are arguments for the fluoridation of water?
Answer
-
Reduction in tooth decay
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Increased risk of fluorosis
-
Protects people who don't have good dental hygiene
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Impossible to set safe limits due to varied intake
-
Ethical issues of being forced to take a treatment
-
Reduced risk of heart disease
Question 20
Question
Which of these are arguments against the fluoridation of water?
Answer
-
Reduction in tooth decay
-
Increased risk of fluorosis
-
Protects people who do not have good dental hygiene
-
Impossible to set safe limits due to varied intake
-
Ethical issues with being forced to take a treatment
-
Reduced risk of heart disease