chemical analysis Flashcards
test for chlorine (CL2)
Damp blue litmus paper held over gas
Turns from blue/red to white
(bleaching agent)
test for ammonia NH3
Red Litmus paper in gas turns blue
name 8 cations
Li+
Na+
K+
Ca2+
Cu2+
Fe2+
Fe3+
NH4 +
Flame colour for lithium
red
Flame colour for sodium
yellow
Flame colour for copper
blue-green
Flame colour for potassium
lila
Flame colour for Calcium
orange-red
what is the regular colour of a bunsen flame flame
non-luminous blue flame
what precipitate does iron II make
green
How to conduct a flame test
Dip a piece of nichrome / platinum wire into hydrochloric acid.
These wires don’t colour the flame, and the acid cleans the wire.
Dip the wire into a sample of solid or solution.
This causes some of the sample to stick onto the wire.
Place the tip of the wire into a non-luminous Bunsen flame.
what precipitate does copper II make
blue
what precipitate does ammonium make
no precipitate just gas = red to blue litmus
what precipitate does iron III make
brown
What is the method for the reaction of copper or iron II or iron III with NaOH
Place about 1cm cubed of the salt solution to be tested in a test tube.
Slowly add drops of 0.5 mol dm-3 sodium hydroxide until you observe a change.
Then continue to add more sodium hydroxide and record your observations.
What is the method for the reaction of ammonium with NaOH
With ammonium place about 1cm cubed of the solution to be tested in a test tube.
Add about 2cm3 of the sodium hydroxide solution to it
Place the test tube in a beaker of warm water and hold a piece of damp red indicator to the mouth of the tube
Name 5 anions
CO3 2-
SO4 2-
Cl-
Br-
I-
which a 3 anions are hallides
Chloride
Bromide
Iodide
test for carbonate and result
Dilute HCl
Look for effervescence
Limewater test of gas
Effervescence with HCl and cloudy limewater
test for sulphate and result
Dilute HCl
Test with Barium chloride
No effervescence with HCl
White precipitate
test for chloride and result
Dissolve sample in water
Add dilute nitric acid
Add silver nitrate solution
White precipitate
test for bromide and result
Dissolve sample in water
Add dilute nitric acid
Add silver nitrate solution
cream precipitate
test for bromide and result
Dissolve sample in water
Add dilute nitric acid
Add silver nitrate solution
Two chemical tests for water
Anhydrous copper sulphate = white –> blue
or
anhydrous cobalt chloride paper = blue –> pink
