2471717
Descripción
Creado por Jamie Caffey
|
Creado por Jamie Caffey
hace más de 11 años
|
|
Pregunta 1
Pregunta
Soft water lathers easily with soap
Respuesta
- True
- False
Pregunta 2
Pregunta
What does hard water produce when it reacts with soap?
Respuesta
-
Scale
-
Scum
Pregunta 3
Pregunta
What ions does hard water contain?
Respuesta
-
Calcium and magnesium
-
Carbon and potassium
Pregunta 4
Pregunta
Temporary hard water produces scale when heated
Respuesta
- True
- False
Pregunta 5
Pregunta
What does scale do?
Respuesta
-
Reduce the efficiency of heating systems and cause blockages
-
Evaporate when heated
Pregunta 6
Pregunta
How are calcium compounds good for our health?
Respuesta
-
Help develop strong bones and teeth. May reduce the risk of heart disease.
-
They do not have any particular health benefits
-
Help with fighting infection
Pregunta 7
Pregunta
Permanent hard water is not softened by boiling and does not produce scale when heated
Respuesta
- True
- False
Pregunta 8
Pregunta
Washing soda is sodium carbonate
Respuesta
- True
- False
Pregunta 9
Pregunta
How are ions precipitated out of hard water?
Respuesta
-
Sodium carbonate reacts with the magnesium and calcium ions in the hard water to form calcium carbonate and magnesium carbonate that will not react with water
-
Filtration
-
Sodium carbonate displaces the magnesium and calcium ions so the hard water turns soft
Pregunta 10
Pregunta
Ion exchange columns contain a resin made of sodium and hydrogen ions
Respuesta
- True
- False
Pregunta 11
Pregunta
How do ion exchange columns work?
Respuesta
-
The calcium and magnesium ions attach to the resin and the water no longer contains any ions
-
The hard water is passed through the exchange column. The calcium and magnesium ions become attached to the resin and the sodium and hydrogen ions take their place in the water. These ions do not react with soap
Pregunta 12
Pregunta
What methods are used to treat water
Respuesta
-
Sedimentation and filtration to remove solids
-
Evaporation and distillation
Pregunta 13
Pregunta
Why is chlorine used in the treatment of water
Respuesta
-
Because it is a law
-
Because chlorine kills microbes in the water
Pregunta 14
Pregunta
What are the issues with using chlorine to treat water?
Respuesta
-
It is poisonous and can produce toxic compounds
-
It is very expensive
Pregunta 15
Pregunta
Why is fluoride added to water?
Respuesta
-
To prevent tooth decay
-
It is added by the government to control the population
-
To help prevent heart disease
Pregunta 16
Pregunta
Some people think that you should be able to choose whether or not to have fluoride in your water
Respuesta
- True
- False
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