Chemistry 2

Question 1

Why do metals give a coloured flame?

Answer 1

When you heat a metal you give it energy which makes it ‘excited’. They have different colours depending on how much energy they give out. After they have been ‘excited’ the electrons drop back to their original energy level.

Question 1

What coloured flame does Strontium have?

Answer 1

red

Question 2

What coloured flame does Barium have?

Answer 2

Green

Question 3

What coloured flame does Calcium have?

Answer 3

Orange/red

Question 4

What coloured flame does Potassium have?

Answer 4

Lilac

Question 5

What coloured flame does Sodium have?

Answer 5

Orange

Question 6

What coloured flame does Lithium have?

Answer 6

Red

Question 7

What coloured flame does Copper have?

Answer 7

Green

Question 8

Describe the process of chromatography

Answer 8

• you draw a line up the length by 1cm and in pencil of the filter paper (chromatography paper).
• then take maximum 3 felt tip pens and dot them on the line far from each other so they don’t touch.
• You then dip the paper in a beaker which contains water that is below the pencil line.
• The colours should then spread up the page.

Question 9

How can you tell a substance is pure or impure by using chromatography?

Answer 9

A pure substance produces one spot on the chromatogram.

An impure substance produces two or more spots.

Question 10

Chromatography - If the dots are further up the filter paper what does that entail?

Answer 10

That means it has a high amount of solvent.

Question 11

Chromatography - What is the mobile phase?

Answer 11

The part that moves - solvent

Question 12

Chromatography - What is the stationary phase?

Answer 12

The part that does not move - filter paper.

Question 13

Chromatography - Why do we use a pencil for the line?

Answer 13

Because it is insoluble

Question 14

Chromatography - Why do we add the filter paper in water?

Answer 14

Because it is a solvent.

Question 15

Chromatography - If something is attracted to the mobile phase it….

Answer 15

moves the most

Question 16

Chromatography - If something is attracted to the stationary phase it….

Answer 16

doesn’t move that much

Question 17

Chromatography - How do you work out the retention factor?

Answer 17

Distance spot has moved / distance solvent has moved

Question 18

Chromatography - Why do we work out the retention factor?

Answer 18

It allows for more accurate comparison of substances.

Question 19

How do you test for hydrogen?

Answer 19

you put a lit splint into a test tube - squeaky pop.

Question 20

How do you test for Chlorine?

Answer 20

You use damp blue litmus paper - it turns white (gets bleached).

Question 21

How do you test for Oxygen?

Answer 21

You put a glowing splint into the test tube - it will relight the splint.

Question 22

How do you test for sulfate ions?

Answer 22

you add dilute hydrochloric acid, then barium chloride

Question 23

How do you test for carbonate ions?

Answer 23

You add dilute acid

Question 24

How do you test for chloride, bromide and iodide ions?

Answer 24

You add dilute nitric acid, then silver nitrate.

Question 25

What colour precipitation forms with carbonate ions?

Answer 25

White

Question 26

what colour precipitate forms with Halide ions?

Answer 26

cream

Question 27

What colour precipitate forms with sulfate ions?

Answer 27

white

Question 28

Why do we use the instrumental analysis technique instead of flame testing?

Answer 28

Because it is more accurate and specific.

Question 29

When blue precipitate is formed what does this mean is present in the stuff?

Answer 29

copper

Question 30

When a reddish brown precipitate is formed what does this mean?

Answer 30

Iron (III)

Question 31

When a dirty green precipitate is formed what does this mean?

Answer 31

Iron(II)

Question 32

When a pale pink precipitate is formed what does this mean?

Answer 32

Magnesium