Chemical tests

Cards (18)

What must you do to the nichrome wire before conducting a flame test?
You first need to sterilise the nichrome wire by dipping it in dilute HCl and holding it over the flame. Once it burns without any colour, you can begin the flame test.
How do you conduct a fame test? 
Hold the unknown substance over a roaring blue flame and observe the flame's colour change.
flame tests - Lithium?
red flame
flame tests - sodium?
yellow flame
flame tests - potassium? 
lilac flame
flame tests - calcium? 
orange-red flame
flame tests - copper?
blue green
How do you test for cation precipitates? 
Add sodium hydroxide to form a coloured insoluble hydroxide also known as a precipitate.
What is the colour of the precipitate of Copper (Cu2+)? 
Blue
What is the colour of the precipitate of Iron (Fe2+)? 
Green
What is the colour of the precipitate of Iron (Fe3+)? 
Brown
Which cations give similar results to each other?
Aluminium, Calcium and Magnesium all form white precipiates after their reactions with NaOH.
How do you test for anion halide ions? 
Add six drops of nitric acid, then add 6 drops of silver nitrate. A coloured ppt should form.
What is the coloured ppt for chloride?  
white
is the coloured ppt for chloride soluble?
yes it is soluble
what is the coloured ppt for bromide? 
cream ppt
is the coloured ppt for bromide soluble?
it is slightly soluble (dissolves in concentrated ammonia)
what is the coloured ppt for iodide? 
yellow