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water
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Question | Answer |
---|---|
what is the composition of water | 2 hydrogen atoms and 1 oxygen atom |
what is the test for water | anhydrous copper sulphate turns from white to blue |
what causes water hardness | calcium and magnesium ions |
give two methods of getting rid of hard water | boiling and using an ion exchange resin |
how is scum formed | calcium ions and soap form scum |
explain the term electrolysis | electrolysis is the production of a chemicl change by electricity |
why is sulphuric acid added to the water in the electrolysis experiment | to help the water conductg electricity |
give an advantage of hard water | provides calcium for bones and teeth |
give a disadvantage of hard water | blocks pipes, leaves scale on kettles and boilers |
how can we test to show oxygen is produced during electrolysis | use a glowing splint - it reignites |
how can be test to show hydrogen is produced during electrolysis | use a glowing splint - it burns with a pop |
in the ion exchange resin what ion replaces the calcium ion | sodium ions |
when water is boiled what is the dissolved hydrogen carbonate changed to . | solid limestone called 'fur' |
what is soft water | water that lathers easily with water |
The water treatment process involves 5 stages which of the 5 stages involves adding a substance to the water | chlorination, fluoridation and settling |
what is the name of the chemical added to get rid of germs | chlorine |
whatis the name of the chemical added to help to reduce tooth decay | fluoride |
whaqt is the name of the chemical used to take the cloudiness out of the water | aluminium sulphate |