Wrong Qs

Question 1

Explain fractional distillation in terms of intermolecular forces

Answer 1

• fractions all have different boiling points

- larger chain hydrocarbons have stronger intermolecular forces

Question 2

Which of these dissolve in water and why?

Choose from: alcohol, ester and carboxylic acids

Answer 2

• alcohol and carboxylic acids
• a presence of O-H group can form strong bonds with the H20
• ester is COO so doesn’t have this

Question 3

How can you check if a substance is a polymer?

Answer 3

• add bromine water
• if it turns from orange-brown to colourless, it’s a monomer as only monomers have double bonds
• polymers should stay orange-brown

Question 4

What is the use of LPG and bitumen?

Answer 4

• LPG = used in cooking

- Bitumen = roofing/ road surfaces

Question 5

What does volatile mean?

Answer 5

• they evaporate easily and quickly

Question 6

What can esters used in perfumes?

Answer 6

• volatile

- pleasant-smelling

Question 7

Why are shorter chain hydrocarbons used?

Answer 7

• more reactive = more polymers

- more flammable and volatile

Question 8

Describe reaction of 2 alchohols:

Answer 8

• 100 cm3 of water to the conical flask
• record the initial temperature of the water
• place some alcohol into the spirit burner, put the lid on and record the mass
• ignite spirit burner
• stir the water gently with the thermometer until 30C
• extinguish the flame of the spirit burner and record the final temperature of the water
• record the final mass including the unburned alcohol and lid
• repeat the experiment with different alcohol in the spirit burner
• Record the mass of water
• repeat the experiment with different alcohol in the spirit burner
• energy released per gram of alcohol (J) = mass of water (g) × temperature change (°C) × 4.2 ÷ mass of alcohol (g)