Structure 1. Models of the particulate nature of matter

1.1 Introduction to the particulate nature of matter

1.2 The nuclear atom

1.3 Electron configurations

1.4 The mole

1.5 Ideal gases

Structure 2. Models of bonding and structure

2.1 The ionic model

2.2 The covalent model

2.3 The metallic model

2.4 From models to materials

Structure 3. Classification of matter

3.1 The periodic table

3.2 Functional groups: Organic compounds

Reactivity 1. What drives chemical reactions?

1.1 Measuring enthalpy changes

1.2 Energy cycles

1.3 Energy from fuels

Reactivity 2. How much, how fast and how far?

2.1 Amount of chemical change

2.2 Rate of chemical change

2.3 Extent of chemical change

Reactivity 3. What are the mechanisms of chemical change?

3.1 Proton transfer reactions

3.2 Electron transfer reactions

3.3 Electron sharing reactions (Radicals)

3.4 Electron-pair sharing reactions

IB Chemistry SL 3.3 Electron sharing reactions (Radicals) Question Bank

[Maximum number: 5]

Alkanes are commonly occurring organic compounds.

(a)

Ethane can be converted to chloroethane by reacting with chlorine gas, $\mathrm{Cl}_{2}(\mathrm{~g})$ , in the presence of UV light.

[ 5 ]

(i)

State the type of reaction and the name of the mechanism by which it occurs.

[ 1 ]

(ii)

Explain the reaction mechanism by writing equations for each step.

One initiation step:
Two propagation steps:

One termination step:

[ 4 ]

[Maximum number: 1]

Chlorine undergoes many reactions.

(a)

(i)

State the type of reaction occurring when ethane reacts with chlorine to produce chloroethane.

[ 1 ]

[Maximum number: 2]

Halogenoalkanes are used as refrigerants and solvents.

(a)

Substance X undergoes nucleophilic substitution with a hydroxide nucleophile.

[ 2 ]

(i)

Contrast homolytic and heterolytic fission.

Homolytic fission:

Heterolytic fission:

[ 2 ]

[Maximum number: 5]

Bromomethane was used as a pesticide until it was found to be ozone-depleting.

(a)

State the equation for the reaction between methane and bromine to form bromomethane.

[ 1 ]

(b)

Explain, using equations, the complete free-radical mechanism for the reaction of methane with bromine, including necessary reaction conditions.

[ 4 ]

[Maximum number: 4]

Ethane reacts with chlorine in the presence of sunlight.

(a)

Complete the overall equation for this reaction by stating the products.

\mathrm{C}_{2} \mathrm{H}_{6}+\mathrm{Cl}_{2} \rightarrow

[ 1 ]

(b)

State the type of mechanism by which this reaction occurs.

[ 1 ]

(c)

Traces of butane, $\mathrm{C}_{4} \mathrm{H}_{10}$ , are also found amongst the products of this reaction. Explain how this product arises.

[ 2 ]

[Maximum number: 4]

Nitrous acid, $\mathrm{HNO}_{2}(\mathrm{aq})$ and hydrochloric acid, HCl(aq) are both inorganic acids.

(a)

Picric acid, carbolic acid and aspirin are trivial names of chemical substances.

They can cause misunderstanding when communicating information internationally.

[ 4 ]

(i)

Ethyl ethanoate can be produced by the reaction of ethanol with ethanoic acid. Both reactants can be synthesized from ethane through a series of reactions, the first of which is shown.

\mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{~g})+\mathrm{Cl}_{2}(\mathrm{~g}) \rightarrow \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}(\mathrm{~g})+\mathrm{HCl}(\mathrm{~g})

The first step in this reaction, initiation, is given by the following equation.

\mathrm{Cl}_{2} \rightarrow 2 \mathrm{Cl} \cdot

State an essential condition for this reaction.

[ 1 ]

(ii)

Deduce two propagation steps and one termination step for this reaction.

[ 3 ]

(a)

Ethane, a member of the homologous series of alkanes, can react with bromine.
Explain the free-radical mechanism of this reaction, including any necessary reaction conditions.

[ 4 ]

[Maximum number: 1]

Which species will most readily react with propane?

Br atom

$\mathrm{Br}_{2}$ molecule

$\mathrm{Br}^{-}$ ion

$\mathrm{Br}^{+}$ ion

[Maximum number: 1]

Which describes the reaction between a halogen and ethane?

Mechanism

Bond fission in halogen

free radical

homolytic

free radical

heterolytic

addition

homolytic

addition

heterolytic

[Maximum number: 1]

What is formed in a propagation step of the substitution reaction between bromine and ethane?

$\mathrm{CH}_{3} \mathrm{CH}_{2} \cdot$

$\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}$

H•

$\mathrm{Br}^{-}$

0 selected

Question 1

Question 1(b)

Question 1(b)(i)

Question 1(b)(ii)

Question 1

Question 1(d)

Question 1(d)(i)

Question 4

Question 4(d)

Question 4(d)(ii)

Question 2

Question 2(a)

Question 2(b)

Question 2

Question 2(a)

Question 2(b)

Question 2(c)

Question 2

Question 2(b)

Question 2(b)(v)

Question 2(b)(vi)

Question 4

Question 4(b)

Question 24

Question 25

Question 26