Carbon Chemistry

Question 1

What are the properties of cycloalkanes?

Answer 1

• They are saturated hydrocarbons ( C-C single bonds)
• Insoluble
• Used for fuels and solvents

Question 2

What are hydrocarbons?

Answer 2

Compounds that contain hydrogen and carbon only.

Question 3

What is the lowest number of carbon atoms possible in a cycloalkane?

Answer 3

3 carbon atoms, called cyclopropane

Question 4

What is a homologous series?

Answer 4

A family of chemicals that have similar chemical properties and the same general formula. (eg: alkanes, alkenes, cycloalkanes, alcohols, carboxylic acids).

Question 5

What are alkanes?

Answer 5

Alkanes are a homologous series that contain carbon atoms joined together by single bonds, which are surrounded by hydrogen. They are hydrocarbons.

Question 6

What is the general formula of alkanes?

Answer 6

CnH2n+2

Question 7

What is the general formula for cycloalkanes?

Answer 7

CₙH₂ₙ

Question 8

Are alkanes insoluble?

Answer 8

Yes

Question 9

What is an unsaturated bond?

Answer 9

C to C double bond.

Question 10

Name the first eight members of the alkane series.

Answer 10

Methane CH₄, ethane C₂H₆, propane C₃H₈, butane C₄H₁₀, pentane C₅H₁₂, hexane C₆H₁₄, heptane C₇H₁₆, octane C₈H₁₈.

Question 11

In homologous series’, what happens to the melting / boiling point as the size of the molecule increases?

Answer 11

As the size of the molecule increases, the melting / boiling point increases.

Question 12

What are isomers?

Answer 12

They have the same molecular formula but a different structural formula.

(eg: butane C₄H₁₀ and 2-methylpropane C₄H₁₀)

Question 13

What are the properties of alkenes?

Answer 13

• Unsaturated hydrocarbons (contains at least one double bond between carbon atoms)
• Names end in -ene
• Double bond can be anywhere in the carbon chain
• Insoluble in water
• Can be used to make polymers and alcohols

Question 14

What is the general formula of the alkenes?

Answer 14

CₙH₂ₙ

Question 15

How do you name branched alkanes?

Answer 15

1) Draw out full structural formula.

2) Look for longest chain of carbon atoms.

3) Which side is the branch closest to and call the starting carbon C₁.

4) Give the other carbons in the chain positions.

5) See what position the branch is on and give a prefix.

If there is 1 C in the branch, methyl
2 C in the branch, ethyl etc.

Question 16

What is the name of this branched alkane: CH₃CH(CH₃)CH₂CH(CH₃)CH₂CH₃.

Answer 16

2, 4 - dimethylhexane

Question 17

Name the first 3 members of the cycloalkanes series

Answer 17

Cyclopropane - C₃H₆
Cyclobutane - C₄H₈
Cyclopentane - C₅H₁₀

Question 18

How do you name alkenes?

Answer 18

1) Look for the longest continuous chain - name it after the corresponding alkane, (eg: ethane, but-1-ene) etc

2) Give the double bond a position, eg: position 2

3) The position of the double bond goes inside the name, eg: pent-2-ene

4) If a branch is present, give it a position from the side the double bond is closest to.

Question 19

How can you tell an alkene apart from an alkane / cycloalkane?

Answer 19

You test for unsaturation.

An alkene decolourises bromine water.

Bromine water remains red / orange when placed into an alkane / cycloalkane.

Question 20

What is a polymer?

Answer 20

A very long chain molecule, made up of thousands of smaller molecules, called monomers.

Monomers are alkenes.

Question 21

How do you name a polymer?

Answer 21

Put the word ‘poly’ in front of the monomer’s name.

eg: ethene → (poly)ethene

   vinylchloride → (poly)vinylchloride

Question 22

How do monomers react?

Answer 22

Addition polymerisation

Question 23

How do you draw a section of a polymer?

Answer 23

1. Draw three monomers.
2. Move the side atoms so they line up vertically.
3. Connect them and add side bonds with brackets at the ends.

Question 24

What does it mean when alkenes are unsaturated?

Answer 24

More atoms can be added to them

Question 25

What are the 3 addition reactions?

Answer 25

- alkene + hydrogen —> alkane - alkene + halogen —> dihaloalkane - alkene + water —> alcohol

Question 26

How can you identify an alcohol?

Answer 26

- Identified by **-ol** at the end of the name - Contains a **hydroxyl group** (-OH) - Alcohols begin with **methanol** as it has **single** bonds

Question 27

How do you name alcohols?

Answer 27

1. Identify the **longest chain** 2. Prioritise **OH** functional group 3. Identify **branches**

Question 28

What are uses of alcohols.

Answer 28

- Used as **solvents** - Used in cleaning products as they are **good solvents** and they **evaporate quickly** - Can be used as **fuels**

Question 29

What are some trends seen with alcohols?

Answer 29

- As the **chain length increases**, the **flammability decreases** - Alcohols are soluble in water and forms solutions but as the **chain length increases**, the **solubility decreases** - **melting and boiling point increases** as **carbon length increases** as there are **stronger intermolecular forces**.

Question 30

What is a source of error for measuring heat energy emitted by an alcohol?

Answer 30

**Heat energy** loss to surroundings

Question 31

What is the general formula for alcohols?

Answer 31

CₙH₂ₙ₊₁OH

Question 32

How can you identify a carboxylic acid?

Answer 32

- Has the **-COOH** functional group, the **carboxyl** group - Names end in ‘**-oic acid**’

Question 33

What is the general formula for carboxylic acids?

Answer 33

CₙH₂ₙ₊₁COOH

Question 34

How do you name branched carboxylic acids?

Answer 34

1. Identify **Carbon 1**; the **COOH** functional group and name from there 2. Find **longest chain** 3. Identify which carbon(s) have **branch(es)**

Question 35

What are the physical and chemical properties of carboxylic acids?

Answer 35

- As they increase in size, their **melting and boiling points** increase due to **stronger intermolecular forces**. - **ONLY** methanoic, ethanoic, propanoic and butanoic acid are **miscible** with water, meaning they can **mix** with water. Thereafter, the **solubility decreases** as **size increases**.

Question 36

What are uses of carboxylic acids?

Answer 36

- preservatives, soaps and medicines - ex: **vinegar**is a **solution of ethanoic acid**. It’s used in household products because it’s non-toxic.