C9 Separate Chemistry 2

Question 1

How can you test for metal ions using a flame?

Answer 1

1. Take a nichrome wire loop and dip it into hydrochloric acid and rinse in distilled water
2. Dip the wire in a sample of the metal compound and put the loop in a blue Bunsen flame

Question 2

What colour does lithium turn in a flame test?

Answer 2

Red

Question 3

What colour does sodium turn in a flame test?

Answer 3

Yellow

Question 4

What colour does potassium turn in a flame test?

Answer 4

Purple

Question 5

What colour does calcium turn in a flame test?

Answer 5

Orange-red

Question 6

What colour does copper turn in a flame test?

Answer 6

Blue-green

Question 7

How can you test for metal ions with a precipitate?

Answer 7

Add sodium hydroxide

Question 8

What colour does aluminium turn in the precipitate test?

Answer 8

White —> colourless

Question 9

What colour does calcium turn in the precipitate test?

Answer 9

White

Question 10

What colour does copper turn in the precipitate test?

Answer 10

Blue

Question 11

What colour does iron(II) turn in the precipitate test?

Answer 11

Green

Question 12

What colour does iron(III) turn in the precipitate test?

Answer 12

Brown

Question 13

How do you test for ammonia?

Answer 13

Add sodium hydroxide and gently heat

Question 14

What is the positive test for ammonia?

Answer 14

Damp red litmus paper turns blue

Question 15

How do you test for halide ions?

Answer 15

Add dilute nitric acid and silver nitrate

Question 16

What colour is chlorine in the halide tests?

Answer 16

White

Question 17

What colour is bromide in the halide tests?

Answer 17

Cream

Question 18

What colour is iodide in the halide tests?

Answer 18

Yellow

Question 19

How do you test for carbonate ions?

Answer 19

Add dilute acid to make carbon dioxide and then bubble in limewater

Question 20

How do you test for sulfate ions?

Answer 20

Add some dilute hydrochloric acid to stop any precipitation reactions occurring and then add some barium chloride solution which forms a white precipitate

Question 21

What are the advantages of flame photometry?

Answer 21

1. Very sensitive
2. Very fast
3. Very accurate

Question 22

What does an unsaturated compound mean?

Answer 22

It contains at least one double bond

Question 22

What does a saturated compound mean?

Answer 22

It only contains single bonds

Question 22

How do you test for alkenes?

Answer 22

Add bromine water to an alkene. When shaken together, the alkene decolourises the orange bromine water to colourless

Question 23

What is addition polymerisation?

Answer 23

When an unsaturated molecule opens up its double bonds to form a polymer chain

Question 24

What are the properties and uses of poly(ethene)?

Answer 24

Properties: flexible, electrical insulator, cheap Uses: Plastic bags, wire insulation

Question 25

What are the properties and uses of poly(propene)?

Answer 25

Properties: flexible, strong, tough Uses: Crates, furniture, ropes

Question 26

What are the properties and uses of poly(chloroethene)?

Answer 26

Properties: Tough, cheap Uses: Window frames, water pipes

Question 27

What are the properties and uses of poly(tetrafluoroethene)?

Answer 27

Properties: Unreactive, tough, non-stick Uses: Non-stick pans, waterproof clothing

Question 28

What is condensation polymerisation?

Answer 28

When two monomers with two functional groups on each end of the molecule react together to create a long chain of alternating monomers with a molecule of water lost

Question 29

How are polyesters formed?

Answer 29

When a dicarboxylic acid monomer and a diol monomer react together to form an ester link

Question 30

What are some naturally occurring polymers?

Answer 30

1. DNA 2. Amino acids

Question 31

What are the advantages of disposing polymers in landfill sites?

Answer 31

Cheaper

Question 32

What are the disadvantages of disposing polymers in landfill sites?

Answer 32

1. Uses up lots of valuable land 2. Most polymers are non-biodegradable

Question 33

What are the advantages of disposing polymers by combustion?

Answer 33

Can produce lots of energy which can be used to generate electricity

Question 34

What are the disadvantages of disposing polymers by combustion?

Answer 34

1. Toxic gases can be released 2. Carbon dioxide also released contributing to global warming

Question 35

What are the advantages of recycling polymers?

Answer 35

1. Reduces the amount of non-biodegradable waste filling up landfill 2. Reduces emissions of greenhouse and toxic gases which can be released from burning polymers 3. Reduces the amount of crude oil needed to produce more plastics 4. Saves money and creates jobs

Question 36

What are the disadvantages of recycling polymers?

Answer 36

1. Difficult and expensive 2. Over time, the strength of a polymer could decrease 3. Melting polymers down could released dangerous gases into the atmosphere

Question 37

How is a carboxylic acid formed?

Answer 37

Alcohols can be oxidised to form with an oxidising agent to form a carboxylic acid

Question 38

How is ethanol produced?

Answer 38

1. Yeast is mixed with a carbohydrate (e.g. sugar beet) and sealed in a temperature between 30C-40C (the enzyme's optimum temperature) 2. The enzymes in the yeast ferment the glucose to make alcohol 3. Once the concentration of alcohol is around 15%, the yeast gets killed off 4. The mixture can then be distilled to produced more concentrated alcohol

Question 39

How are nanoparticles used in sun cream?

Answer 39

Titanium dioxide nanoparticles blocks UV light on skin

Question 40

What are composites?

Answer 40

Composites are made of different materials depending on the properties of the materials it is made from