Metal Ion Flame Tests - CORE PRACTICAL

Question 1

When burnt, potassium ions will cause the flame to become which colour?

Answer 1

Lilac

Question 2

When burnt, lithium ions will cause the flame to become which colour?

Answer 2

Crimson

Question 3

When burnt, calcium ions will cause the flame to become which colour?

Answer 3

Orange-red

Question 4

When burnt, sodium ions will cause the flame to become which colour?

Answer 4

Yellow

Question 5

When burnt, copper ions will cause the flame to become which colour?

Answer 5

Blue-green

Question 6

The burning of which metal ion results in a lilac flame?

Answer 6

Potassium (K+)

Question 7

The burning of which metal ion results in a crimson flame?

Answer 7

Lithium (Li+)

Question 8

The burning of which metal ion results in an orange-red flame?

Answer 8

Calcium (Ca 2+)

Question 9

The burning of which metal ion results in a yellow flame?

Answer 9

Sodium (Na+)

Question 10

The burning of which metal ion results in a blue-green flame?

Answer 10

Copper (Cu 2+)

Question 11

State a problem for interpreting the result of a flame test if the sample used consists of multiple different ions

Answer 11

Flame colours of some may be masked possibly leading to incorrect interpretations

Question 12

What are flame tests used for?

Answer 12

Identifying the metal ions in an ionic compound

Question 13

The wire loop used to hold an ionic compound sample in the flame for a metal ion flame test should be made of which alloy?

Answer 13

Nichrome

Because of its high melting point and that non of its constituents lend any colour to the flame

Question 14

To clean it, the nichrome wire loop should be submerged in what at the start of the practical?

Answer 14

Dilute Hydrochloric acid (HCl)

Question 15

Give two pieces of equipment required for a metal ion flame test practical

Answer 15

Bunsen Burner
Nichrome wire loop

Question 16

What is a nichrome wire loop used for in a metal ion flame test?

Answer 16

Holding an ionic compound sample in the blue bunsen flame

Question 17

Describe in 4 steps the process of conducting a metal ion flame test

Answer 17

1) Submerge a nichrome wire loop in dilute HCl to clean it
2) Place cleaned loop in the ionic compound sample you wish to test
3) Hold loop with sample on in a blue bunsen burner flame
4) Observe and record any colour change to the Bunsen’s flame

Question 18

Why should the nichrome wire loop be first submerged in dilute HCl?

Answer 18

To clean it, ensuring more accurate results by the removal of the residue of other compounds which could otherwise interfere with or obscure the colour change caused by the new ionic compound