4.15 - Flame Tests and the Test for Ammonium Ions Flashcards Preview

Chemistry - Topic 04: Inorganic Chemistry and the Periodic Table > 4.15 - Flame Tests and the Test for Ammonium Ions > Flashcards

Flashcards in 4.15 - Flame Tests and the Test for Ammonium Ions Deck (23)
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1
Q

What safety precautions should be considered when doing a flame test?

A

Wearing safety glasses, a lab coat, and doing the experiment in a fume cupboard

2
Q

What is used to do the flame test?

A

A nichrome wire

3
Q

What must be done to the wire before used for the flame test?

A

It must be sterilised with nitric acid

4
Q

Why?

A

Because it may have other metal compounds on it which would change the colour of the flame

5
Q

What is added to the metal before putting into the flame?

A

Hydrochloric acid

6
Q

Why?

A

Because it forms a metal chloride, which is more volatile and so will give better results

7
Q

What is the main impurity in every flame test?

A

Sodium

8
Q

What is another problem with flame tests?

A

Human perception of colour

9
Q

What colour do lithium ions produce?

A

Red

10
Q

What colour do sodium ions produce?

A

Orange-yellow

11
Q

What colour do potassium ions produce?

A

Lilac

12
Q

What colour do rubidium ions produce?

A

Red/Purple

13
Q

What colour do caesium ions produce?

A

Blue/Violet

14
Q

What ions produce no colour?

A

Beryllium and magnesium

15
Q

What colour do calcium ions produce?

A

Brick red

16
Q

What colour do strontium ions produce?

A

Crimson red

17
Q

What colour do barium ions produce?

A

Apple green

18
Q

What causes these colours to be emitted?

A

Electron transitions

19
Q

What happens when electrons absorb energy?

A

They move to a higher energy level

20
Q

When is the colour produced?

A

When they return to the ground state

21
Q

What is the test for the ammonium ion?

A

Adding sodium hydroxide and warming the mixture

22
Q

What dies this produce?

A

Ammonia

23
Q

How can this be detected?

A

By using damp red litmus paper, which turns blue