🥂 • Lesson 2.8 : Organic Chemistry (Chem)

Question 1

What is a displayed formula?

Answer 1

A diagram showing all atoms and all bonds in a molecule.

Question 2

What is a saturated compound?

Answer 2

A compound where all carbon–carbon bonds are single bonds.

Question 3

What is an unsaturated compound?

Answer 3

A compound with one or more carbon–carbon double or triple bonds.

Question 4

What is a homologous series?

Answer 4

A family of similar compounds with similar chemical properties.

Question 5

What are the characteristics of a homologous series?

Answer 5

Same general formula and a trend in physical properties.

Question 6

Name and imagine the drawing of the displayed formulas of methane and ethene.

Answer 6

Methane: CH₄ → one carbon, four hydrogens, all single bonds.

Ethene: C₂H₄ → two carbons, four hydrogens, one double bond between the carbons.

Question 7

How can you tell the type of compound from the name ending?

Answer 7

-ane: Alkane (single bonds)
-ene: Alkene (double bond)
-ol: Alcohol (OH group)

Question 8

Name the three fossil fuels.

Answer 8

Coal, natural gas, petroleum.

Question 9

What is the main constituent of natural gas?

Answer 9

Methane (CH₄).

Question 10

What are hydrocarbons?

Answer 10

Compounds that contain only hydrogen and carbon.

Question 11

What is petroleum?

Answer 11

A mixture of hydrocarbons.

Question 12

How is petroleum separated into useful fractions?

Answer 12

By fractional distillation.

Question 13

What is refinery gas used for?

Answer 13

For heating and cooking.

Question 14

What is gasoline/petrol used for?

Answer 14

As fuel for cars.

Question 15

What is naphtha used for?

Answer 15

As a chemical feedstock.

Question 16

What is diesel oil/gas oil used for?

Answer 16

As fuel in diesel engines (ex. Some trains)

Question 17

What is bitumen used for?

Answer 17

For making roads.

Question 18

What is the kerosene fraction used for?

Answer 18

Fuel for jet planes.

Question 19

What is the lubricating oil fraction used for?

Answer 19

Reducing friction in machinery.

Question 20

How does chain length change from the bottom to the top of the fractionating column?

Answer 20

Chain length decreases.

Question 21

How does boiling point change from the bottom to the top of the fractionating column?

Answer 21

Boiling point decreases.

Question 22

What type of bonding is found in alkanes?

Answer 22

Single covalent bonds.

Question 23

Are alkanes saturated or unsaturated hydrocarbons?

Answer 23

Saturated hydrocarbons.

Question 24

What is the main chemical property of alkanes?

Answer 24

They are generally unreactive, except for combustion.

Question 25

What type of bonding is found in **alkenes**?

Answer 25

A double carbon–carbon covalent bond.

Question 26

Are **alkenes** saturated or unsaturated hydrocarbons?

Answer 26

Unsaturated hydrocarbons.

Question 27

How can you distinguish between saturated and unsaturated hydrocarbons?

Answer 27

By reacting them with **aqueous bromine** — unsaturated hydrocarbons decolourise bromine water.

Question 28

How are alkenes and hydrogen made from alkanes?

Answer 28

By cracking large alkane molecules at high temperature using a catalyst.

Question 29

What happens when alkenes react with bromine?

Answer 29

The bromine water turns from **orange to colorless**, showing the alkene is unsaturated.

Question 30

What happens when alkenes react with hydrogen?

Answer 30

They undergo an addition reaction to form alkanes, using a nickel catalyst.

Question 31

What happens when alkenes react with steam?

Answer 31

They form alcohols in the presence of an acid catalyst.

Question 32

What are the products of the complete combustion of ethanol?

Answer 32

Carbon dioxide (CO₂) and water (H₂O).

Question 33

What are two common uses of ethanol?

Answer 33

As a solvent or as a fuel.

Question 34

What are polymers?

Answer 34

Large molecules made from many smaller repeating units called monomers.

Question 35

How is poly(ethene) formed?

Answer 35

By the addition polymerisation of ethene monomers.

Question 36

How can you identify the repeat unit in an addition polymer?

Answer 36

Look for a section of the polymer chain that repeats and comes from the original alkene monomer.

Question 37

What is the difference between *addition* and *condensation polymerisation*?

Answer 37

Addition polymerisation uses only **one type of monomer** and forms **no** by-products, Condensation polymerisation involves **two different monomers** and produces a small **by-product (like water).**

Question 38

What is nylon and how is it structured?

Answer 38

Nylon is a **polyamide** made from two different monomers (a diamine and a dicarboxylic acid) that join to form long chains with amide (–CONH–) links.

Question 39

What monomer is used to make poly(ethene)?

Answer 39

Ethene (C₂H₄).

Question 40

What are some common uses of poly(ethene)?

Answer 40

Plastic bags, bottles, and packaging.