C3- Organic Chemistry

Question 1

Name the first four members of the alkanes.

Answer 1

1) CH₄➡️Methane (Monkeys).
2) C₂H₆➡️Ethane (Eat).
3) C₃H₈➡️Propane (Peanut).
4) C₄H₁₀➡️Butane (Butter).

Question 2

What is the common functional group of all alcohols?

Answer 2

-OH.

Question 3

What are the key properties of alcohols?

Answer 3

• Flammable➡️Burns in air (forming CO₂ + H₂O).
• Dissolves in water.
• Reacts with sodium to create hydrogen gas.

Question 4

What are the main uses of alcohols?

Answer 4

• Alcoholic beverages.
• Fuel➡️Brazil ferments sugar for ethanol.
• Solvents (substance good at dissolving things).

Question 5

What is the name of the alcohol found in alcoholic drinks?

Answer 5

Ethanol.

Question 6

Write the structural formula of propanol.

Answer 6

CH₃CH₂CH₂OH.

Question 7

What is the common functional group of all carboxylic acids?

Answer 7

-COOH.

Question 8

Why do carboxylic acids make weakly acidic solutions with water?

Answer 8

They partially dissociate in water➡️Not all molecules dissociate.

Question 9

What common compound do carboxylic acids react with and what are the products?

Answer 9

They react with alcohols to make esters.

Question 10

Why is vinegar an aqueous solution?

Answer 10

The main acid in vinegar is ethanoic acid which is too concentrated when its pure and is extremely corrosive (would kill you).

Question 11

How can ethanol be made into ethanoic acid?

Answer 11

React it with oxygen using chemical oxidising agents or by the action of microbes.

C₂H₅OH + O₂➡️CH₃COOH + H₂O.

Question 12

Why do many perfumes contain ethanol?

Answer 12

It is a solvent so when mixed with water it evaporates easily.

Question 13

Why do carboxylic acids have properties similiar to all other acids?

Answer 13

They produce H⁺ (hydrogen) ions in aqueous solutions.

Question 14

What two ingredients must be combined to make an ester and how?

Answer 14

An alcohol and carboxylic acid with an acid catalyst.

Question 15

Why is ester formation a condensation reaction?

Answer 15

Because it creates water as a by-product.

Question 16

Name a common ester.

Answer 16

Ethylethanoate.

Question 17

Describe some uses of esters, why are their properties suited to each?

Answer 17

Flavourings and perfumes because they are volatile compounds and have distinctive smells.

Question 18

What is a strong acid?

Answer 18

An acid that ionises completely in aqueous solutions.

E.g: HCl➡️H⁺+Cl^-.

Question 19

What is a weak acid?

Answer 19

An acid which does not ionise completely in aqueous solutions.

E.g: CH₃COOH⇌CH₃COOH + H⁺.

Question 20

Why is it important to review our use of organic chemicals?

Answer 20

Advantages and disadvantages may change over time as resources are used up or there are new developments or new research.

Question 21

What is the common functional group of all esters?

Answer 21

-COO-