1. What does soluble and insoluble mean?
25/04/2017
What does soluble and insoluble mean?
What would be produced when something is insoluble?

2. They love an exam question on this!
25/04/2017
Making a salt!
They love an exam question on this!

3. Making a salt
Lead nitrate and potassium iodide are soluble in water. They react to make Lead iodide and Potassium nitrate. Lead iodide is a yellow precipitate and so is insoluble. It could be removed by filtering the mixture, washing it with water to clean it and then drying it using a Bunsen burner or warm oven.

4. 25/04/2017
How can we test for ions?

5. Ion tests
Flame tests are used to identify the metal ion in a salt.
Dip the flame test loop in acid to clean it. Hold it in the flame to check it is clean, if it is not, put it in acid again. When clean, dip the loop into the sample and hold the loop in the flame.

6. Flame tests
25/04/2017
Compounds containing lithium, sodium, potassium, calcium and barium ions can be recognised by burning the compound and observing the colours produced:
Lithium
Red
Sodium
Yellow
Potassium
Lilac
Calcium
Brick red
Barium
Green
2.15
Be able to describe tests to show the following ions are present in solids or solutions:
a) Na+, K+, Ca2+, Cu2+ using flame tests
b) CO32- using dilute acid and identifying the carbon dioxide evolved
c) SO42- using dilute hydrochloric acid and barium chloride solution
d) Cl- using dilute nitric acid and silver nitrate solution

7. Testing for carbonate ions
25/04/2017
Limewater
Limewater turns milky/cloudy
2.15
Be able to describe tests to show the following ions are present in solids or solutions:
a) Na+, K+, Ca2+, Cu2+ using flame tests
b) CO32- using dilute acid and identifying the carbon dioxide evolved
c) SO42- using dilute hydrochloric acid and barium chloride solution
d) Cl- using dilute nitric acid and silver nitrate solution
What does this tell us is being made?
Calcium carbonate + hydrochloric acid calcium chloride + carbon dioxide + water

8. Test for carbonate ions CO3-
Carbon dioxide gas is given off when an acid is added to a substance containing carbonate ions.
Limewater is used to identify the gas given off. If the limewater changes colour from colourless to cloudy / milky white then the gas is Carbon dioxide.

9. Testing for chloride and sulfate ions
25/04/2017
For each test state: 1) The colour of the precipitate
2) What compound it is
Test 1: Chloride ions
Add a few drops of dilute nitric acid to the chloride ion solution followed by a few drops of silver nitrate.
Precipitate formed = silver chloride (white)
2.15
Be able to describe tests to show the following ions are present in solids or solutions:
a) Na+, K+, Ca2+, Cu2+ using flame tests
b) CO32- using dilute acid and identifying the carbon dioxide evolved
c) SO42- using dilute hydrochloric acid and barium chloride solution
d) Cl- using dilute nitric acid and silver nitrate solution
Test 2: Sulphate ions
Add a few drops of dilute hydrochloric acid to the sulphate ion solution followed by a few drops of barium chloride.
Precipitate formed = barium sulphate (white again)

10. Using this spectroscope I can see this:
Spectroscopy
25/04/2017
Spectroscopy is kind of like a flame test but using a “spectroscope” to see the results:
Using this spectroscope I can see this:
Each different element has a different “signature” when viewed through a spectroscope. This analysis enables us to detect the presence of small amounts of elements and this led to the discovery of new elements including rubidium and caesium.
2.16
Know that chemists use spectroscopy (a type of flame test) to detect the presence of very small amounts of elements and that this led to the discovery of new elements, including rubidium and caesium