9) Separate Chemistry 2

Question 1

What colour does lithium burn?

Answer 1

Crimson

Question 2

What colour does copper burn?

Answer 2

Blue-green

Question 3

What colour does calcium burn?

Answer 3

Orange-red

Question 4

What colour does potassium burn?

Answer 4

Lilac

Question 5

What colour does sodium burn?

Answer 5

Yellow

Question 6

What is the process of the flame test practical?

Answer 6

1) Submerge nichrome wire loop in dilute hydrochloric acid to clean
2) Place nichrome wire loop onto sample to be tested
3) Hold nichrome wire loop in Bunsen burner’s blue flame
4) Observe any change in colour to flame

Question 7

What do flame tests identify?

Answer 7

Metal ions in an ionic compound

Question 8

What reactants produce precipitates?

Answer 8

The reaction of metal ions and sodium hydroxide

Question 9

How can metal ions precipitate out of solution?

Answer 9

React with sodium hydroxide

Question 10

What is the formula for sodium hydroxide?

Answer 10

NaOH

Question 11

Can precipitates be dissolved in water?

Answer 11

No, they are insoluble solids

Question 12

What precipitate does magnesium form?

Answer 12

White magnesium hydroxide

Question 13

What is the formula for producing the white precipitate magnesium hydroxide?

Answer 13

Mg2+(aq) + 2OH-(aq) –> Mg(OH)2(s)

Question 14

What state are precipitates?

Answer 14

Solid

Question 15

What precipitate does aluminium form?

Answer 15

White aluminium hydroxide

Question 16

What is the formula for producing the white precipitate aluminium hydroxide?

Answer 16

Al3+(aq) + 3OH-(aq) –> Al(OH)3(s)

Question 17

How can aluminium hydroxide be distinguished from other hydroxides?

Answer 17

Is dissolved in excess sodium hydroxide producing a colourless solution

Question 18

What precipitate does calcium form?

Answer 18

White calcium hydroxide

Question 19

What is the formula for producing the white precipitate calcium hydroxide?

Answer 19

Ca2+(aq) + 2OH-(aq) –> Ca(OH)2(s)

Question 20

How can magnesium hydroxide and calcium hydroxide be distinguished?

Answer 20

Flame test

Question 21

What precipitate does copper form?

Answer 21

Blue copper(II) hydroxide

Question 22

What is the formula for producing blue copper(II) hydroxide?

Answer 22

Cu2+(aq) + 2OH-(aq) –> Cu(OH)2(s)

Question 23

What precipitates do iron form?

Answer 23

Green iron(II) hydroxide
Brown iron(III) hydroxide

Question 24

What precipitate does ammonia form?

Answer 24

Water and ammonia

Ammonia gas evolves out of solutions

Question 25

What is the formula for producing water and ammonia?

Answer 25

NH4+(aq) + OH-(aq) --> NH3(g) + H2O(l)

Question 26

What is the chemical test for ammonia?

Answer 26

Placing damp litmus paper at mouth of test tube | Blue litmus paper if ammonia present

Question 27

What colour does damp litmus paper turn if ammonia is present?

Answer 27

Blue

Question 28

What ion characteristic do all carbonates have?

Answer 28

CO32- ions

Question 29

What does the reaction of a carbonate and dilute acid give?

Answer 29

Salt Carbon dioxide Water

Question 30

What is the test for carbonates?

Answer 30

(carbon dioxide test) Bubble hydrochloric acid and carbonate gas through limewater If solution turns cloudy carbon dioxide is present

Question 31

What is the test for sulfates?

Answer 31

1) Add dilute hydrochloric acid to solution to remove carbonate ions which could disrupt results 2) Add barium chloride and a white precipitate barium sulfate will form

Question 32

What ions do sulfates contain?

Answer 32

SO4 2-

Question 33

What type of ions are halide?

Answer 33

Anions | Negatively charged

Question 34

What is the test for halides?

Answer 34

1) Add dilute nitric acid to remove carbonates | 2) Add silver nitrate, halides will form a precipitate with the silver ions

Question 35

What colours can the precipitate silver halide be?

Answer 35

White (silver chloride) Cream (silver bromide) Pale yellow (silver iodide)

Question 36

What is the order of testing for cations?

Answer 36

1) Flame test 2) Coloured precipitate with sodium hydroxide 3) Test evolving gas for ammonium

Question 37

What is the order of tests for anions?

Answer 37

Carbonates- test for carbon dioxide gas Sulfates- presence of white barium sulfate Halides- colour of silver halide corresponds to halide anion in a positive result

Question 38

What are the 3 anion types?

Answer 38

Carbonates Sulfates Halide ions

Question 39

Why does the test for an anion have to be carried out in a logical order?

Answer 39

If any HCl or BaCl2 is added to the test for a carbonate or sulfate, there will be chloride ions in the solution These will be tested and there will be a false positive result for chloride ions

Question 40

What are advantages of instrumental methods? (3)

Answer 40

Greater sensitivity and accuracy Quicker at producing results Able to analyse tiny samples

Question 41

What are disadvantages of instrumental methods? (3)

Answer 41

Instruments are often expensive Special training needed for use Results are often only useful when compared to data from known substances

Question 42

What is the use of flame emission spectroscopy?

Answer 42

Working out the identity and concentration of the metal ions present in a solution

Question 43

What is the process of flame emission spectroscopy? (2)

Answer 43

1) Place sample of metal solution into a flame, light will be given off 2) Light given off is captured by a spectroscope which generates a line spectrum by distinguishing between light with different wavelengths

Question 44

How is the concentration of an ion shown on a line spectra?

Answer 44

The intensity of line spectra