Organic Chem Questions

Question 1

How many isomers have the molecular formula C5H12?
A2
B3
C4
D5

Answer 1

B 3

Question 2

How many structural isomers have the molecular formula C4H9Br? A2
B3
C4
D5

Answer 2

C

Question 3

How many secondary amines have the molecular formula C4H11N?
A2
B3
C4
D5

Answer 3

B

Question 4

Which statement is not correct about the pollutant sulfur dioxide?
A It can be removed from car exhaust gases by a catalytic converter.
B It can be removed from power station flue gases by reaction with calcium oxide.
C It can cause respiratory problems.
D It can cause acid rain.

Answer 4

A

Question 5

Which statement is correct about thermal cracking?
A A pressure between 100 and 200 kPa is used.
B Aromatic hydrocarbons are the major products.
C C–C bonds are broken.
D Zeolite catalysts are used.

Answer 5

C

Question 6

The combustion of petrol in car engines produces the pollutant nitrogen monoxide.
Give an equation for a reaction that removes nitrogen monoxide in a catalytic converter.

Answer 6

2NO + 2CO -> N2 + 2CO2

Question 7

The table shows possible conditions and products for the cracking of alkanes. Which row is correct?
Catalytic

Answer 7

Slight temperature high pressure
Mainly branched Oakland’s and aromatics

Question 8

Which of these substances does not contribute to the greenhouse effect?
A Unburned hydrocarbons.
B Carbon dioxide.
C Water vapour.
D Nitrogen.

Answer 8

C

Question 9

An excess of methane reacts with chlorine in the presence of ultraviolet radiation.
What are the main products of this reaction?
A CCl4 and H2
B CCl4 and HCl
C CH3Cl and H2
D CH3Cl and HCl

Answer 9

D

Question 10

Q11.
Which correctly represents an incomplete combustion of pentane?
A C5H12 + 8O2 ⟶ 5CO2 + 6H2O
B C5H12 +8O2 ⟶4CO+CO2 +6H2O
C C5H12 +6O2 ⟶4CO+CO2 +6H2O
D C5H12 +5O2 ⟶4CO+CO2 +4H2O+2H2

Answer 10

C

Question 11

Which species is produced in a propagation step during the reaction of propane with an excess of chlorine in the presence of UV light?
A H•
B C3H5Cl
C C3H6CL2
D C6H14

Answer 11

C

Question 12

Which molecule is not produced when ethane reacts with bromine in the
presence of ultraviolet light?
A C2H4Br2 B HBr
C H2
D C4H10

Answer 12

C

Question 13

Sulfur dioxide (SO2) is produced when some fossil fuels are burned. Which of the following statements is true?
A Sulfur dioxide can be removed from waste gases in a power station by an acid-base reaction with calcium oxide.
B Sulfur dioxide is insoluble in water.
C Sulfurdioxideisabasicoxide.
D Sulfurdioxideisanioniccompound.

Answer 13

A

Question 14

Tetradecane (C14H30) is an alkane found in crude oil. When tetradecane is heated to a high temperature, one molecule of tetradecane decomposes to form one molecule of hexane and three more molecules.
Which of the following could represent this reaction?
A C14H30 → C6H14 + C4H8 + 2C2H4
B C14H30 → C6H14 + C6H12 + C2H4
C C14H30 → C5H12 + 3C3H6
D C14H30 → C6H14 + C2H6 + 2C3H6

Answer 14

A

Question 15

Write the overall equation for the reaction of fluorine with methane to form trifluoromethane (CHF3)

Answer 15

CH4 + 3F2 -> CHF3 + 3HF

Question 16

Identify a bond in a CFC that is broken by UV radiation to produce a reactive intermediate that catalyses the decomposition of ozone. Write an overall equation for the decomposition of ozone

Answer 16

Bond broken - C-Cl
Reactive intermediate - chlorine atom
Overall equation - 2O3 -> 3O2

Question 17

Explain why sulphur compounds found in crude oil should be removed fro mute fractions before they are used for central heating fuel

Answer 17

S02 produced in combustion
Which causes acid rain

Question 18

Explain why 1,1,1-trifluoroethane does not lead to the depletion of the ozone in the upper atmosphere

Answer 18

Does not contain chlorine

Question 19

Give a reason why bonds in molecules such as carbon dioxide and 1,1,1-trifluoroethane absorb infrared radiation

Answer 19

Polar bonds as they vibrate/stretch

Question 20

State the benefit to life on Earth of ozone in the upper atmosphere.

Answer 20

Absorbs UV radiation

Question 21

CFC-11 is a greenhouse gas that can contribute to global warming.
State and explain how CFC-11 is able to contribute to global warming.

Answer 21

Absorbs UV radiation
Molecule has polar bonds

Question 22

Which is a propagation step in the chlorination of methane?
A H●+Cl2 →HCl+Cl●
B Cl●+CH4 →CH3Cl+H● C ●CH3 +Cl●→CH3Cl
D ●CH3 +Cl2 →CH3Cl+Cl●

Answer 22

D

Question 23

Which equation represents a propagation step?
A •CH2Cl + Cl• → CH2Cl2
B •CH3 + •CH3 → C2H6
C Cl2 → Cl• + Cl•
D CH3Cl + Cl• → •CH2Cl + HCl

Answer 23

D

Question 24

Which statement is correct about the fractional distillation of crude oil?
A A zeolite catalyst is used.
B Each fraction contains a mixture of hydrocarbons.
C Gaseous fractions are formed by breaking covalent bonds.
D The fractionating column is hottest at the top.

Answer 24

B

Question 25

Which equation is a propagation step in the conversion of trichloromethane into tetrachloromethane by reaction with chlorine in the presence of ultraviolet light?
A CHCl3 +Cl2 ⟶CCl4 +HCl
B ●CCl3 + ●Cl ⟶ CCl4
C CHCl3 +●Cl⟶CCl4 +●H
D ●CCl3 +Cl2 ⟶CCl4 +●Cl

Answer 25

D

Question 26

Which species is produced in a propagation step during the reaction of propane with an excess of chlorine in the presence of UV light?
A H•
B C3H5Cl
C C3H6CL2
D C6H14

Answer 26

C

Question 27

Tetradecane (C14H30) is an alkane found in crude oil. When tetradecane is heated to a high temperature, one molecule of tetradecane decomposes to form one molecule of hexane and three more molecules.
Which of the following could represent this reaction?
A C14H30 → C6H14 + C4H8 + 2C2H4 B C14H30 → C6H14 + C6H12 + C2H4 C C14H30 → C5H12 + 3C3H6
D C14H30 → C6H14 + C2H6 + 2C3H6

Answer 27

A