4.6 - Chemical analysis Flashcards

1
Q

Test for hydrogen

A
  1. Collect sample of gas in test tube
  2. Ignite using lit splint
  3. Result = squeaky pop
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Test for oxygen

A
  1. Collect a sample of gas in test tube
  2. Place glowing splint in test tube
  3. Result = splint relights
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Chemical test for water

A
  1. Add anhydrous copper sulfate
  2. Result = Changes from white to blue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Physical test for water

A
  1. Measure BP
  2. Result = BP is 100 degrees
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Test for carbon dioxide

A
  1. Bubble a sample of the gas through limewater.
  2. Result = solution turns cloudy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Test for chlorine

A
  1. Place damp blue litmus paper in a sample of gas.
  2. Result = it turns white (bleaches).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Test for ammonia

A
  1. Place damp red litmus paper in a sample of gas.
  2. Result = it turns blue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How to conduct a flame test.

A
  1. Dip a piece of nichrome / platinum wire into hydrochloric acid. These wires don’t colour the flame, and the acid cleans the wire.
  2. Dip the wire into a sample of solid or solution. This causes some of the sample to stick onto the wire.
  3. Place the tip of the wire into a non-luminous Bunsen flame.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does a flame test test for?

A

What type of metal cation is in a substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Flame colour of lithium (Li) ?

A

Red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Flame colour of sodium (Na) ?

A

Yellow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Flame colour of potassium (K) ?

A

Lilac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Flame colour of calcium (Ca) ?

A

Orange-red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Flame colour of copper (Cu) ?

A

Blue-green

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do you conduct a sodium hydroxide (NaOH) test?

A
  1. Dissolve the sample in water.
  2. Add a few drops of NaOH(aq).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a sodium hydroxide test testing for?

A

To see in Cu, Fe(II) or Fe (III) is present

17
Q

What colour precipitate is formed with Cu?

A

Blue

18
Q

What colour precipitate is formed with Fe(II) ?

A

Green

19
Q

What colour precipitate is formed with Fe(III) ?

A

Brown

20
Q

How to conduct an ammonium test

A
  1. Dissolve the sample in water.
  2. Add some NaOH(aq) and warm it.
  3. Test the gas evolved with damp red litmus paper
21
Q

What happens if ammonium ions are present?

A

Litmus will turn blue.

22
Q

How to conduct a halide test?

A
  1. Dissolve the sample in water.
  2. Add nitric acid (HNO3).
  3. Add silver nitrate (AgNO3) solution.
23
Q

What are we testing for with a halide test?

A

If Cl−, Br− or I− ions are present

24
Q

What colour precipitate does Cl form?

A

White

25
Q

What colour precipitate does Br form?

A

Cream

26
Q

What colour precipitate does I form?

A

Yellow

27
Q

Why do we add HNO3 in the halide test?

A
  1. Ag ions also form precipitates with OH and CO3.
  2. The HNO3 reacts with those anions and prevents false positives
28
Q

How to conduct a test for carbonates?

A
  1. Add hydrochloric acid (HCl), look for effervescence.
  2. If there is effervescence, bubble the gas through limewater
29
Q

If carbonate ions are present what colour does the limewater go?

A

Cloudy

30
Q

Why do we check the gas is CO2 in the carbonate test?

A

To prevent false positives

31
Q

How to conduct a test for sulfates?

A
  1. Add hydrochloric acid (HCl), look for effervescence.
  2. If there’s no effervescence, add barium chloride (BaCl2) solution.
32
Q

What happens if sulfate ions are present?

A

White precipitate will be formed

33
Q

Why do we add HCl is the sulfate test?

A

Because carbonate atoms also form a white precipitate white Ba ions. So we prevent false positives.