3.2 Water Flashcards
What causes tempory hardness?
Dissolved calcium hydrogen carbonate which is Ca(HCO3)2
What causes permanent hardness?
Dissolved calcium sulphate CaSO4
What substance softens hard water?
Sodium carbonate which is washing soda
What does filtration involve?
Putting the water through beds of sand and gravel. This removes large solids from the water
What does sedimentation involve?
Adding a chemical to remove very small solids from the water
What does chlorination involve ?
It involves chlorine gas being added to the water which kills bacteria
Name 3 common examples of how water can get polluted.
Fertilisers, pesticides, run off from nuclear power plants, lead from old pipes.
explain the causes and symptoms of fluorosis
Fluorosis is caused by taking in to much fluoride which can weaken bones and teeth
Explain the distribution of hard and soft water in the uk
The NW is softer the SE is harder (in general)
How much fluoride and for how long would it take for you to have skeletal fluorosis
10-20mg every day for 20 years
What is the chemical formula for water?
H20
What two chemicals are most renowned for causing a water sample to be hard?
Calcium (Ca) Magnesium (Mg)
What group on the periodic table causes hard water?
Group 2
What is the common name for the waste product produced when soap solution is added to a hard water sample?
Scum (calcium stearate)
“Drinking hard water can have health benefits” True or false?
True