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.
