Tests for Ions and Gases Flashcards
1
Q
What is the name for a negative ion?
A
anion
2
Q
What are the three types of anions tested for?
A
- carbonates
- sulfates
- halides
3
Q
How to test for carbonate
A
- add HCl/nitric acid to solid
- should produce bubbles in the cold
- test for carbon dioxide with limewater - should turn milky
4
Q
How to test for sulfates
A
- add HCl acid to aqueous solution of solid
- add barium chloride solution
- produces WHITE precipitate
5
Q
How to test for halides
A
- add nitric acid to aqueous solution of solid
- add silver nitrate solution
- chloride: white precipitate
- bromide: cream precipitate
- iodide: yellow precipitate
6
Q
What is the name for a positive ion?
A
cation
7
Q
What are the two types of tests for anions?
A
- flame tests
- precipitates
8
Q
How to carry out a flame test
A
- clean nichrome or platinum wire by dipping it in HCl acid and then roaring bunsen flame
- repeat until wire does not give colour in flame
- dip it again in fresh HCl acid
- dip in solid and hold in flame
9
Q
Colours:
- sodium
- lithium
- potassium
- calcium
A
- orange/yellow
- red
- lilac
- brick red
10
Q
What is a precipitate?
A
insoluble solid formed from a reaction taking place in aqueous solution
11
Q
How to form precipitate of metal hydroxide
A
- add NaOH solution to aqueous solution of metal salt
12
Q
colours of precipitate:
- copper
- Fe 2+
- Fe 3+
A
- blue
- green
- brown
13
Q
How to test for ammonia
A
- add Na OH solution to solution of solid and warm mixture
- should release pungent-smelling gas
- turns damp red litmus paper blue
14
Q
How to test for chlorine
A
- bleaches litmus paper
- turns starch-iodide paper blue
15
Q
How to test for carbon dioxide
A
- turns limewater milky
