Which of the following substances is removed by filtration?
Dissolved salts
Insoluble particles
Microbes
What is the name of the process that kills microbes during water purification?
Chlorination
Precipitation
Crystallisation
Which process is used to make drinking water from seawater?
Filtration
Desalination
Which process uses high pressure and a porous membrane to purify water?
Distillation
Reverse osmosis
What is the name of the process used to purify water which involves boiling the water and then cooling it to condense the vapour?
Chromatography
The chart below shows the average water consumption of a particular household. What is the most effective way that the household could reduce its water consumption?
Install a toilet with a short flush
Wash clothes less frequently
Take fewer showers
What are the three main processes of water purification in the correct order?
Filtration – Sedimentation – Chlorination
Sedimentation – Chlorination – Filtration
Sedimentation – Filtration – Chlorination
Which of the following is a disadvantage of adding fluoride to the drinking supply?
It is a form of mass medication
It strengthens the enamel of teeth
It reduces tooth decay
Desalination is commonly used to purify water in the Middle East. Which of the following is a reason why this method is suitable?
Rainfall is high
Many of the countries are poor financially
Many of the countries have coastlines
Using the information below, what is the percentage decrease in mean decayed, missing, and filled teeth (DMFT) in France between 1980-1990 and 2000-2009?
3.1%
73.8%
26.2%