Topic 9

Question 1

Describe the colour you would expect from a flame test if lithium was present

Answer 1

Red

Question 2

Describe the colour you would expect from a flame test if sodium was present

Answer 2

Yellow

Question 3

Describe the colour you would expect from a flame test if potassium was present

Answer 3

Lilac

Question 4

Describe the colour you would expect from a flame test if calcium was present

Answer 4

Orange-red

Question 5

Describe the colour you would expect from a flame test if copper was present

Answer 5

Blue-green

Question 6

Describe the chemical test for ammonia

Answer 6

Makes​ ​damp​ ​red​ ​litmus​ ​paper​ ​turn​ ​blue
It​ ​also​ ​forms​ ​a​ ​white​ ​smoke​ ​of​ ​ammonium​ ​chloride​ ​when​ ​hydrogen​ ​chloride​ ​gas,from​ concentrated​ ​hydrochloric​ ​acid,​ ​is​ ​held​ ​near​ ​it

Question 7

Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained ALUMINIUM to test for cations

Answer 7

White (dissolves when an excess of NaOH is added)

Question 8

Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained CALCIUM to test for cations

Answer 8

White

Question 9

Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained IRON (II) to test for cations

Answer 9

Green

Question 10

Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained COPPER to test for cations

Answer 10

Blue

Question 11

Describe the precipitate colour you would expect to see when NaOH is added to a sample that contained IRON (III) to test for cations

Answer 11

Brown

Question 12

Describe what you would expect to see when NaOH is added to a sample that contained AMMONIUM to test for cations

Answer 12

Pungent smelling gas is produced and turns damp red litmus paper blue

Question 13

Describe how a test for cations would be carried out

Answer 13

1. add a small amount of the solution into a test tube
2. add a few drops of sodium hydroxide to the solution
3. record colour of precipitate
4. add sodium hydroxide until it is in an excess
5. Record the colour

Question 14

Describe how flame tests for cations would be carried out

Answer 14

1. Light the Bunsen burner and open air hole for a blue flame
2. Take a sample of the test substance using a wire loop
3. Hold the sample on the edge of the flame and observe a colour

Question 15

What is the test for a SULFATE ANION

Answer 15

○ Add​ ​dilute​ ​HCl​ ​followed​ ​by​ ​barium​ ​chloride​ ​solution to the sample
○ A​ ​WHITE​ ​precipitate​ ​will​ ​form​ ​when​ ​sulfate​ ​ions​ ​are​ ​in​ ​this​ ​solution

Question 16

What is the test for a CARBONATE ANION

Answer 16

Gas​ ​produced​ ​bubbled​ ​through​ ​limewater,​ ​if​ ​the​ ​limewater​ ​goes​ ​cloudy,the​ ​gas​ ​is​ ​CO2​ ​​ ​(carbonates​ ​react​ ​with​ ​dilute​ ​acids​ ​to​ ​produce​ ​CO2​)

Question 17

What is the method for testing Chloride​ ​ion,​ ​Cl-​ ,​ ​ ​bromide​ ​ion,​ ​Br-​ ,​ ​ ​iodide​ ​ion,​ ​I-​ ,​ ​ ​using​ ​dilute​ ​nitric​ ​acid​ ​and​ ​silver nitrate​ ​solution

Answer 17

First​ ​add​ ​dilute​ ​nitric​ ​acid,​ ​followed​ ​by​ ​silver​ ​nitrate​ ​solution
○ Chloride​ ​gives​ ​a​ ​WHITE​ ​precipitate
○ Bromide​ ​gives​ ​a​ CREAM precipitate
○ Iodine​ ​gives​ ​a YELLOW precipitate

Question 18

What are the first 4 alkanes

Answer 18

Methane
Ethane
Propane
Butane

Question 19

What is the general formula of an alkane

Answer 19

CnH(2n+2)

Question 20

Why are alkanes saturated carbons

Answer 20

Because they have no C=C bond

Question 21

Explain how bromine water is used to distinguish between alkanes and alkenes 

Answer 21

Alkenes​ ​react​ ​with​ ​bromine​ ​water,​ ​turning​ ​it​ ​from​ ​orange​ ​to​ ​colourless​ ​–​ ​alkanes DO​ ​NOT​ ​react​ ​with​ ​bromine​ ​water

Question 22

What is the general formula for alkenes

Answer 22

CnH(2n)

Question 23

Describe how the complete combustion of alkanes and alkenes involves the oxidation of the hydrocarbons to produce carbon dioxide and water

Answer 23

The​ ​combustion​ ​of​ ​hydrocarbons​ ​releases​ ​energy.​ ​During​ ​combustion,​ ​the carbon​ ​and​ ​hydrogen​ ​in​ ​the​ ​fuels​ ​are​ ​oxidised​ ​to​ ​produce​ ​carbon​ ​dioxide​ ​and water
alkane/alkene​ ​+​ ​oxygen​ ​→​ ​carbon​ ​dioxide​ ​+​ ​water

Question 24

Do alkanes OR alkenes undergo addition polymerisation

Answer 24

ALKENES

Question 25

How do we show an addition polymerisation reaction

Answer 25

Carbon double bond is lost Monomer is put in square brackets withlines from each C overlapping n at the bottom right corner outside brackets

Question 26

Why are alkenes unsaturated hydrocarbons

Answer 26

They contain a C=C double bond

Question 27

What are polyesters

Answer 27

Condensation polymers

Question 28

What is condensation polymerisation

Answer 28

When two different monomers react together producing a water molecule

Question 29

How is an ester link formed

Answer 29

A molecule containing two carboxylic acid groups and a molecule containing two alcohol groups forms an ester link when they react together

Question 30

What are some of the problems with the disposal of polymers

Answer 30

Most are go into landfill sites and some are burnt which releases toxic gases

Question 31

Name an advantage and disadvantage of recycling polymers

Answer 31

Landfill sites is a waste of a nonrenewable resource as polymers are made from crude oil Recycling means that less waste goes into landfill however this is expensive due to the collection and sorting

Question 32

Name a polymer based on amino acids

Answer 32

Proteins

Question 33

Name a polymer based on sugars

Answer 33

Starch

Question 34

Name a polymer made from nucleotides

Answer 34

DNA

Question 35

What is the functional group of an alcohol

Answer 35

-OH

Question 36

How do alcohols differ in molecular formula

Answer 36

CH2

Question 37

What is the functional group of carboxylic acids

Answer 37

-COOH

Question 38

How is ethanoic acid produced

Answer 38

Ethanol is oxidised by: Reacting with oxygen (burns in air) Chemicals called oxidising agents The action of microbes

Question 39

How can you obtain a concentrated solution of ethanol

Answer 39

By fractional distillation Works because ethanol has a lower boiling point than water

Question 40

How big are nano particles compared to atoms

Answer 40

They consist of only a few 100 atoms

Question 41

What are nano particles useful for

Answer 41

Sunscreen Carbon nanotubes in tennis rackets Future drug delivery systems

Question 42

Why are nano particles useful for sunscreen

Answer 42

Absorb harmful ultraviolet light from the Sun but cannot be seen on the skin

Question 43

What are the risks associated with the use of nano particles

Answer 43

Attract toxic substances to the surfaces can be inhaled take a long time to breakdown If absorbed they an alter reactions in the body

Question 44

List the properties of glass ceramics

Answer 44

Transparent hard but brittle poor conductors of heat and electricity

Question 45

List the properties of clay ceramics

Answer 45

Opaque hard but brittle poor conductors of heat and electricity

Question 46

List the properties of polymers

Answer 46

Transparent translucent or opaque poor conductors of heat and electricity often tough and ductile

Question 47

List the properties of metals

Answer 47

Can be polished to a shine good conductors of heat and electricity hard tough and ductile