Free Radical Substitution Past Paper Questions

Question 1

A refrigerator contains 1.41 kg of 1,1,1-trifluoroethane (CF3CH3).
Calculate the number of molecules of 1,1,1-trifluoroethane in the refrigerator. Give your answer to an appropriate number of significant figures

Answer 1

Mass (g) /Mr * NA

Question 2

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

Answer 2

Bonds vibrate

Question 3

State the initiation step for chlorodifluoromethane

Answer 3

CHClF2 => Cl⚫️+ ⚫️CHF2

Question 4

Give one reason why 2,3,3,3-tetrafluoropropene is a mor environmentally acceptable refrigerant than chlorodifluoromethane

Answer 4

C-F bond too strong so no free radical substitution take place = no depletion of ozone

Question 5

State what the ⚫️ represents in Cl ⚫️

Answer 5

Free electron

Question 6

Two products are formed when propene reacts with hydrogen bromide. Draw the structure of the intermediate that leads to the formation of the major product in the reaction of propene with hydrogen bromide.
Give the name of this type of immediate

Answer 6

Carbonium ions

Question 7

How do chlorine atoms act as a catalyst in the decomposition of ozone into oxygen

Answer 7

Chlorine lowers Ea

Question 8

Suggest a formula, other than C2Br6, of a bromine containing compound formed when dibromomethane, CH2Br2, reacts with bromine

Answer 8

CBr4