Chemistry GCSE: C7 Organic Chemistry Flashcards Preview

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Flashcards in Chemistry GCSE: C7 Organic Chemistry Deck (65)
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1

Alkanes are hydrocarbons

  1. What elements are hydrocarbons made from?
  2. What type of bonds do alkanes contain? How can you tell?

  1. Hydrocarbons are made from hydrogen and carbon.
  2. Alkanes contain covalent bonds.

 

Covalent bonds are between non-metal atoms and hydrogen and carbon are both non-metals.

2

Name the first four alkanes in order of size starting with the smallest.

Mice Eat Peanut Butter

  1. Methane
  2. Ethane
  3. Propane
  4. Butane

3

What is the general formula for alkanes

CnH2n+2

For example:

Methane has 1 carbon atom so it has (2x1)+2 = 4 hydrogen atoms.

Ethane has 2 carbon atom so it has (2x2)+2 = 6 hydrogen atoms.

 

4

  1. What is the chemical formula for Methane.
  2. Draw the displayed formula (a drawing showing all the atoms and bonds for Methane.)

  1. CH4
  2. Diagram below

5

  1. What is the chemical formula for Ethane.
  2. Draw the displayed formula (a drawing showing all the atoms and bonds) for Ethane.

  1. C2H6
  2. Diagram below

6

  1. What is the chemical formula for Propane.
  2. Draw the displayed formula (a drawing showing all the atoms and bonds for Propane.)

  1. C3H8
  2. Diagram below

7

  1. What is the chemical formula for Butane.
  2. Draw the displayed formula (a drawing showing all the atoms and bonds for Butane.)

  1. C4H10
  2. Diagram below

8

Describe the realtionship between the length of a hydrocarbon and...(the first one has been done for you):

  1. How runny the hydrocarbon is (The shorter the hydrocarbon the runnier it is).
  2. The boiling point of the hydrocarbon.
  3. How flamable the hydrocarbon is.
  4. How viscous (sticky) the hydrocarbon is.

  1. The shorter the hydrocarbon the runnier it is.
  2. The shorter the hydrocarbon chain the lower its boiling point.
  3. The shorter the hydrocarbon the more flammable it is.
  4. The longer the hydrocarbon the more viscous it is.

9

Explain why shorter hydrocarbons have lower boiling points than longer hydrocarbons.

They have weaker intermolecular forces.

So it takes less energy to break these

10

Explain why shorter hydrocarbons are runnier/less viscous than longer hydrocarbons.

They have weaker intermolecular forces.

11

Methane has a lower melting and boiling point than propane. Explain why.

Because methane is a shorter molecule. 

So the intermolecular forces between the methane moleculse are weaker.

It therefore takes less energy to break them.

12

Which alkane (methane, ethane, propane or butane) is..

  1. Most flamable 
  2. Most viscous (most sticky)

  1. Methane is most flamable because it is the shortest.
  2. Butane is most viscous because it is the longest.

13

Name 3 fossil fuels

Crude oil

Coal

Natural gas

14

What was crude oil made from

Plankton that died millions of years ago

And was exposed to high temperature and pressure

15

Where is crude oil found

In layers of rock below the sea and the ground

16

Fossil fuels are non-renewable/Finite.

 

What does non-renewable/Finite mean

That we are using them faster than they are made/they will eventually run out.

17

What is fractional distillation used for?

Seperating the hydrocarbons in crude oil.

18

Explain how fractional distillation works.

  1. Crude oil is heated until the hydrocarbons evaporate/vaporise.
  2. The hydrocarbons rise through the column.
  3. The hydrocarbons condense and are extracted in different parts of the column (fractions).
  4. Longer hydrocarbons condense (turn back into a liquid) in the lower parts of the column.

19

Why do shorter hydrocarbons cool and condense in the upper part of the fractional distillation column?

Because they have lower boiling points.

20

Why do longer hydrocarbons cool and condense in the lower part of the fractional distillation column?

Because they have higher boiling points.

21

What are the different hydrocarbons extracted from crude oil used for?

  1. Used as fuels
  2. Used for making polymers (plastics)
  3. Used as solvents (e.g in paints)
  4. Used for making lubricants
  5. Used for making detergents

22

What is cracking used for?

Why is this important?

Breaking long hydrocarbons into short hydrocarbons.

Because short hydrocarbons are more useful than long hydrocarbons.

23

What are the products of cracking used for?

  1. Used as fuels (e.g petrol)
  2. Alkenes made in cracking are used for making polymers (plastics)

24

Describe what happen during catalytic cracking.

  1. The hydrocarbons are heated until they evaporate/vaporise
  2. Then they are passed over a catalyst

25

Describe what happen during steam cracking.

  1. The hydrocarbons are heated until they evaporate/vaporise
  2. Then they are mixed with steam and heated to very high temperatures.

26

TRIPLE:

Name the first 4 alkenes

Ethene

Propene

Butene

Pentene

Eat Peanut Butter Penitently

27

TRIPLE:

What functional group do alkenes have

C=C

28

TRIPLE:

Name the first 4 alkenes

Ethene

Propene

Butene

Pentene

Eat Peanut Butter Penitently

29

TRIPLE:

What is the general formula for alkenes

C2H2n

30

TRIPLE:

What is the chemical formula for

  1. Methene
  2. Ethene
  3. Propene
  4. Butene
  5. Pentene

  1. Methene: Doesn't exist
  2. Ethene: C2H4
  3. Propene: C3H6
  4. Butene: C4H8
  5. Pentene: C5H10