find the relative formula mass (Mr) of water. ( H20)
18
24
36
72
calculate the percentage of nitrogen in NH3.
82.4
78
34.6
The moles of an element = mass of that element/ the relative atomic mass of that element. Sarah has 48 grams of magnesium, she believes she has two moles, is she right?
What are the advantages of hard water?
Prevention of heart disease.
it makes you feel happy
it contains minerals which may be good for your health.
If I add soap to water and it easily forms a lather, is it hard or soft water?
Hard water
Soft water
Which compounds are dissolved into temporary hard water?
Magnesium hydrogen carbonate and Calcium hydrogen carbonate.
Magnesium sulfate and calcium sulfate.
when boiling temporary hard water, what is the product it forms?
rust
limescale
nasty worms
Name the disadvantages of hard water.
more soap is needed to form a suitable lather.
It is bad for your eyes
it produces scum which is difficult to clean
Hard water cannot be used for industrial processes like dying materials.
Advantages of hard water. ( choose 3)
calcium helps growth of healthy bones and teeth.
magnesium helps an effective metabolism
less likely to suffer from heart disease.
the chemicals within it make you happier
it will help you succeed in your life.
calcium + sodium carbonate forms what?
soluble sodium ions + Calcium carbonate (limescale)
calcium stearate.
