Tests for ions and Flame Photometry (Acids 2)

Question 1

How do you carry out a flame test?

Answer 1

You would soak a splint in the solution that you are testing and then hold it IN a bunsen burner flame set to roaring

Question 2

What colour flame does a lithium ion produce?

Answer 2

Red flame

Question 3

What colour flame does a Sodium ion produce?

Answer 3

Yellow flame

Question 4

What colour flame does a potassium ion produce?

Answer 4

Lilac flame

Question 5

What colour flame does a calcium ion produce?

Answer 5

Orange/Red flame

Question 6

What colour flame does a copper ion produce?

Answer 6

Blue/Green flame`

Question 7

Are compounds of sodium potassium, and ammonium soluble?

Answer 7

All compounds of sodium, potassium and ammonium are soluble

Question 8

Are nitrates soluble?

Answer 8

All nitrates are soluble

Question 9

Are chlorides soluble?

Answer 9

All chlorides except for silver and lead chloride are soluble

Question 10

Are sulfates soluble?

Answer 10

All sulfates except for barium, calcium and lead sulfate are soluble

Question 11

Are carbonates soluble

Answer 11

All carbonates except for Sodium, potassium and ammonium are INsoluble

Question 12

Are hydroxides soluble?

Answer 12

All hydroxides except for Sodium, potassium and ammonium hydroxides are INsoluble

Question 13

How do you test for sulfate ions?

Answer 13

Add hydrochloric acid to the solution to acidify it and get rid of any carbonate ions (1). Then add Barium Chloride solution (1). If sulfate ions are present, a white precipitate of Barium Sulfate will form (1).

Barium sulfate is insoluble so will form a precipitate

Question 14

What is the word equation with state symbols for the sulfate ion test?

Answer 14

Metal Sulfate(aq) + Barium Chloride(aq) –> Barium Sulfate(s) + Metal Chloride(aq)

Question 15

Why is it safe to swallow toxic Barium Sulfate tablets?

Answer 15

Because Barium Sulfate is insoluble it won’t be absorbed into the bloodstream

Question 16

How do you test for Halide Ions?

Answer 16

You first add nitric acid to react with any carbonate in the solution (1). You then add silver nitrate solution (1). If there is a halide ion present a coloured precipitate will form (1).

Question 17

What colour precipitate will Chloride ions form?

Answer 17

A white precipitate of silver chloride

Question 18

What colour precipitate will bromide ions form?

Answer 18

A cream coloured precipitate of silver bromide

Question 19

What colour precipitate will iodide ions form?

Answer 19

A yellow precipitate of silver iodide

Question 20

What is the equation for the test for chloride ions?

Answer 20

Ag+(aq) + Cl-(aq) –> AgCl(s)

Question 21

What is the equation for the test for bromide ions?

Answer 21

Ag+(aq) + Br-(aq) –> AgBr(s)

Question 22

What is the equation for the test for iodide ions?

Answer 22

Ag+(aq) + I-(aq) –> AgI(s)

Question 23

How do you test for ammonium ions?

Answer 23

Add a few drops of sodium chloride to the solution then heat gently (1). If ammonium is present ammonia gas will be produced. To test for ammonia gas, hold a damp piece of red litmus paper near the gas and if it turns blue, then ammonia gas is present and therefore ammonium is present in the solution (1).

Question 24

How do you do a precipitate test?

Answer 24

You add a few drops of sodium hydroxide to the solution and if a coloured precipitate forms then cations are present

Question 25

What type of ions do flame tests, ammonium tests and precipitate tests test for?

Answer 25

Cations

Question 26

What type of charge do cations have?

Answer 26

A positive charge

Question 27

What type of ions to halide ion tests, carbonate tests and sulfate ions tests test for?

Answer 27

Anions

Question 28

What type of charge do anions have?

Answer 28

A negative charge

Question 29

What colour precipitate would Calcium ions form?

Answer 29

A white precipitate

Question 30

What colour precipitate would copper ions form?

Answer 30

A blue precipitate

Question 31

What colour precipitate would Iron(II) ions form?

Answer 31

A green precipitate

Question 32

What colour precipitate would Iron(III) ions form?

Answer 32

A brown precipitate

Question 33

What colour precipitate would Aluminium ions form?

Answer 33

A white precipitate that forms and then dissolves (as you add excess sodium hydroxide) into a colourless solution