C25

Question 1

How would we carry out a flame test to test metal ions

Answer 1

Dip a clean loop of wire into the sample being tested

Put the loop into the fame of a Bunsen burner

Observe the colour of flame produced

Question 2

What are the colour of the different compounds if we carry out the flame test

Answer 2

Lithium - red 
Sodium - yellow 
Potassium - lilac 
Calcium - orange red 
copper - blue , green

Question 3

How would you test positively charged ions without using a flame test

Answer 3

we can add sodium hydroxide to some metal ions in a solution , this forms a precipitate and we can identify the ion

Question 4

How do we distinguish between aluminium and calcium ions

Answer 4

if excess sodium hydroxide is added :

Aluminium forms a colourless solution
Calcium remains unchanged

Question 5

Test for ammonia

Answer 5

Makes damp red litmus paper turn blue

Question 6

how do we identify carbonate ions

Answer 6

We can add dilute acid and carbon dioxide will be given off . we can use limewater to test the carbon dioxide

Question 7

How do we identify sulphate ions

Answer 7

First add Hydrochloric acid to the solution to remove any carbonate ions

Then add barium chloride and a white precipitate will form

Question 8

how do we test for chloride ions

Answer 8

Add nitric acid to solution to eliminate carbonate ions

then add silver nitrate to solution and observe colour of precipitate that forms

Question 9

Advantages of instrumental methods ?

Answer 9

They are quicker to carry out
they are more accurate
they are more sensitive

Question 10

what is a flame photometer

Answer 10

Based on flame testing and used to identify an ion in a sample
Uses the emission spectra