THE WIRE LOOP! Made from nichrome and dipped in concentrated hydrochloric acid. This is so that any metals left on the loop react with the acid and dont effect the tests.
THE COMPOUND! Next you dip the clean loop into the compound.
THE FLAME! If the compound contains a certain metal it will turn the flame a certain colour!
LITHIUM! SODIUM! POTASSIUM CALCIUM! (brick red) BARIUM! COPPER!
If you memorise these colours with the metals they indicate then you will be good on any flame test question in the exam.
To test for carbonates you simply use lime water. When carbonates react with dilute hydrochloric acid, they for carbon dioxide and a salt and water. Luckily there is a test for carbon dioxide involving limewater and this helps you to identify if a carbonate is present in a substance.
CALCIUM CARBONATE + HYDROCHLORIC ACID -> CALCIUM CHLORIDE+ CARBON DIOXIDE+ WATER
This means that CO2 is always produced when a carbonate is reacted with hydrochloric acid and so if there is a carbonate present, CO2 will be produced. We can tell if CO2 has been produced by bubbling the gas given off through lime water. This turns the lime water milky and so you can tell if CO2 is produced and there for if there was a carbonate.
THERMAL DECOMPOSITION OF COPPER AND ZINC CARBONATE
When copper carbonate and zinc carbonate are heated, a thermal decomposition reaction takes place!
THIS RESULTS IN A COLOUR CHANGE!!!!!
Strongly heated copper carbonate goes black!
Strongly heated zinc carbonate goes yellow! (As zinc oxide is formed)
Some metal ions form a precipitate, which is an insoluable product that comes out of a solution. This happens when sodium hydroxide solution is added. In the example of calcium chloride a white precipitate of calcium hydroxide is formed (as well as sodium chloride solution).
ALUMINIUM! it produces a white precipitate
CALCIUM! it produces a white precipitate (also)
MAGNESIUM! it produces a white precipitate as well :)
COPPER! it produces a blue precipitate!
IRON (2+) it produces a green precipitate!
IRON! (3+)it produces a brown precipitate!
LEARN THESE AND YOUL BE OKAY!