Organic Chemistry

Question 1

Write the equation of incomplete combustion of propane? With carbon, carbon dioxide and water being the products

Answer 1

C3H8+3½O2=C+CO+CO2+4H2O

Question 2

Write two propagating steps to show how C3H7Cl is formed? Curly arrows is not required

Answer 2

C3H8+Cl.–>C3H7.+HCl
C3H7.+Cl2–>C3H7Cl+Cl.

Question 3

Identify the different C3H7Cl molecules that are produced in this reaction?

Answer 3

The products are 1-chloropropane and 2-chloropropane.

Question 4

Give a reason why a mixture of C3H7Cl molecules is formed?

Answer 4

the chlorine free radicals can remove a hydrogen from either the end carbon atoms or central carbon atoms.

Question 5

Give a reason why some hexane is formed in this reaction.

Answer 5

two propyl free radicals react together

Question 6

Explain the toxicity of carbon dioxide?

Answer 6

• carbon dioxide reacts with haemoglobin in the blood.
• preventing it from carrying oxygen around the body.

Question 7

Explain why coffee grounds might be considered a carbon-neutral fuel (2)

Answer 7

the carbon dioxide released when the fuel is
used to the carbon dioxide that has been used by the plant.

Question 8

Explain how the use of fossil fuels causes climate change? (2)

Answer 8

• carbon dioxide is a greenhouse gas
• increases the greenhouse effect.

Question 9

Write the equation for the complete combustion of octane. State the symbols are not required.

Answer 9

C8H18+ 12½O2= 8CO2+9H20

Question 10

(c) Long chain alkanes are converted into smaller, more useful molecules including alkenes.
(i) Name this process

Answer 10

Cracking

Question 11

Suggest one advantage and one disadvantage of using ripening bananas as a source of ethene for polymer production

Answer 11

• bananas are renewable resource
• it would take a long time

Question 12

State a hazard associated with hydrogen chloride. (1)

Answer 12

HCl is toxic.

Question 13

Suggest how the hydrogen chloride could be removed from the waste gases produced in an incinerator. (1)

Answer 13

pass through water

Question 14

An electrophile
A- accepts a pair of electrons
B- always has a negative charge.
C- always has a positive charge.
D- donates a pair of electrons

Answer 14

A- accepts a pair of electrons

Question 15

Give a reason why petrol should not contain a high proportion of heptane

Answer 15

because petrol burns less efficiently

Question 16

19. Chloroethane, C2H5Cl, can be made from either ethane or ethene.
    (a)(i)What reagent and condition would be used to make chloroethane from ethane?
    Reagent:
    Condition:

Answer 16

Reagent: chlorine
Condition: uv.light

Question 17

(ii) State the type of reaction and mechanism by which this reaction occurs?

Answer 17

free radicals
substitution.

Question 18

(b)(i) What reagent would be used to make chloroethane from ethene?

Answer 18

Hydrogen chloride.

Question 19

Write the equation for the cracking of decane (C10H22) to form 1 molecule of propene as the only alkene

Answer 19

C10H22–>C7H16+C3H6

Question 20

UV radiation causes poly(propene) to degrade. Suggest one advantage and one
disadvantage of this.

Answer 20

Advantage: polypropene will decompose naturally
Disadvantage: cannot be recycled.

Question 21

Which of the following is the correct order for the processes used to obtain petrol from petroleum (crude oil)

Answer 21

D- petroleum–>fractional distillation–> cracking–> reforming–>petrol.

Question 22

Explain the difference between hazard and risk

Answer 22

Hazard is a substance that can cause harm and risk is a chance that harm will result.