4.5 - Organics I Flashcards

1
Q

What is the general formula for alkanes?

A

CnH2n+2

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2
Q

What are alkanes?

A

homologous series of organic molecules (hydrocarbons)

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3
Q

Order of alkanes with increasing no. Carbons

A

-Methane
-Ethane
-Propane
-Butane
-Pentane

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4
Q

Alkanes have similar…

A

chemical reactions

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5
Q

Alkanes have trends in…

A

physical properties (e.g. BP, colour)

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6
Q

What are isomers?

A

molecules with the same formula but different structural formula

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7
Q

What is the general equation for complete combustion?

A

alkane + oxygen —> carbon dioxide + water

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8
Q

When does complete combustion occur?

A

excess of oxygen

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9
Q

When does incomplete combustion occur?

A

not enough oxygen

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10
Q

What are the products of incomplete combustion?

A

-carbon monoxide (CO)
-soot (C)

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11
Q

Why are alkanes combusted?

A

to release energy - most alkanes are used as fuels

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12
Q

Why is carbon monoxide harmful?

A

-toxic gas
-lowers oxygen-carrying capacity of blood

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13
Q

Why is soot harmful?

A

-causes lung disease

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14
Q

Incomplete combustion releases less…

A

energy - LESS USEFUL

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15
Q

Wat are the 2 pollutants that are released as a result of combustion?

A

-carbon dioxide
-sulphur dioxide

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16
Q

Why is carbon dioxide harmful?

A

-greenhouse gas
-traps heat in the atmosphere, causes climate change

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17
Q

Why is acid rain harmful?

A

-corrodes structures
-harmful to plant and aquatic life

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18
Q

How is sulphur dioxide formed as a result of combustion?

A

when sulphur impurities in the fuel combust

19
Q

Why is sulphur dioxide harmful?

A

acid rain

20
Q

What is an alkane reaction with a halogen an example of?

A

substitution reaction

21
Q

What does a halogen reaction with an alkANE require?

A

UV light

22
Q

What happens in a halogen and alkane reaction?

A

hydrogen swaps with a halogen (e.g. chlorine)

23
Q

Why do we use cracking?

A

to break down longer alkanes into useful, shorter ones

24
Q

What are the 2 cracking conditions?

A

-temp (650C)
-catalyst (aluminium oxide)

25
Q

What is the general equation for cracking?

A

long alkane —> shorter alkane + alkene

26
Q

What is the genera formula for alkenes?

A

CnH2n

27
Q

What is the main difference between alkanes and alkenes?

A

alkenes have one C=C double-bond

28
Q

Why are alkenes referred to as unsaturated?

A

they have a C=C double-bond

29
Q

Alkenes reaction with Bromine is an example of what reaction?

A

addition

30
Q

What happens in an addition reaction?

A

C=C breaks and Br atoms are added in

31
Q

Does an addition reaction require UV light?

A

NO

32
Q

Why does an addition reaction require no UV light?

A

alkenes are more reactive than alkanes

33
Q

What is the colour change in an addition reaction?

A

orange —> colourless (bromine water is orange)

34
Q

Bromine reaction is used to test for what?

A

C=C in unsaturated compounds

35
Q

How is an addition polymer formed?

A

when molecules with a C=C add into chains

36
Q

What are the 4 common polymers?

A

-poly(ethene)
-poly(propene)
-poly(chloroethene)
-poly(tetrafluoroethylene)

37
Q

What are the uses of poly(ethene)?

A

-drinks bottles
-shopping bags

38
Q

What are the uses of poly(propene)?

A

-storage boxes
-climbing ropes

39
Q

What are the uses of poly(chloroethene)?

A

-wire insulation
-drainpipes

40
Q

What are the uses of poly(tetrafluoroethene)?

A

-non-stick coating

41
Q

What does inert mean?

A

chemically very unreactive

42
Q

Addition polymers are…

A

inert

43
Q

4 ways to dispose an unwanted addition polymer

A

-reuse it
-recycle it
-incinerate it
-chuck it into landfill