874656
Pregunta 1
Pregunta
True or false? Using hard water makes it more difficult for soap to lather.
Respuesta
- True
- False
Pregunta 2
Pregunta
Which of these rocks helps to cause hardness in water?
Respuesta
-
Gypsum
-
Granite
-
Dolomite
-
Calcite
-
Basalt
Pregunta 3
Pregunta
Which type of deposit forms when hard water reacts with soap?
Respuesta
-
Scale, calcium carbonate
-
Scum, calcium stearate
Pregunta 4
Pregunta
Which type of deposit forms when hard water is boiled?
Respuesta
-
Scale, calcium carbonate
-
Scum, calcium stearate
Pregunta 5
Pregunta
True or false? Calcium carbonate dissolves in carbonic acid (rainwater) to produce calcium ions and hydrogencarbonate ions.
Respuesta
- True
- False
Pregunta 6
Pregunta
Which type of hard water can be softened by heating?
Respuesta
-
Permanent hard water
-
Temporary hard water
Pregunta 7
Pregunta
True or false? Scale is formed upon heating temporary hard water because calcium hydrogencarbonate forms a precipitate.
Respuesta
- True
- False
Pregunta 8
Pregunta
Which of these methods can soften either type of hard water?
Respuesta
-
Washing soda
-
Boiling
-
Ion-exchange column
Pregunta 9
Pregunta
Which ion is exchanged with calcium and magnesium ions in an ion-exchange column?
Respuesta
-
Potassium K+
-
Sodium Na+
-
Cadmium Cd2+
-
Iron Fe3+
Pregunta 10
Pregunta
True or false? Ion-exchange columns do not need to be regularly washed out with saline solution.
Respuesta
- True
- False
Pregunta 11
Pregunta
What is the first stage in the water treatment process?
Respuesta
-
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
Pregunta 12
Pregunta
What is the second stage in the water treatment process?
Respuesta
-
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
Pregunta 13
Pregunta
What is the third stage in the water treatment process?
Respuesta
-
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
Pregunta 14
Pregunta
What is the fourth stage in the water treatment process?
Respuesta
-
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
Pregunta 15
Pregunta
What is often contained in a filter cartridge?
Respuesta
-
Activated carbon
-
Activated boron
-
Ion-exchange column
-
Fractionating column
-
Silver
-
Ruthenium
Pregunta 16
Pregunta
What are health benefits of drinking hard water?
Respuesta
-
Reduced risk of heart disease
-
Reduced risk of cancer
-
Stronger muscles
-
Stronger bones and teeth
Pregunta 17
Pregunta
Which gas is sometimes used as an alternative to chlorine in killing bacteria?
Respuesta
-
Fluorine
-
Hydrogen sulphide
-
Ozone
-
Methane
Pregunta 18
Pregunta
Which ion is sometimes added to water to reduce the risk of tooth decay?
Respuesta
-
Sulphate, SO42-
-
Fluoride, F-
-
Nitrate, NO3-
-
Potassium, K+
Pregunta 19
Pregunta
Which of these are arguments for the fluoridation of water?
Respuesta
-
Reduction in tooth decay
-
Increased risk of fluorosis
-
Protects people who don't have good dental hygiene
-
Impossible to set safe limits due to varied intake
-
Ethical issues of being forced to take a treatment
-
Reduced risk of heart disease
Pregunta 20
Pregunta
Which of these are arguments against the fluoridation of water?
Respuesta
-
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
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