Topic 11 Organic Chemistry

Topic 11 Organic Chemistry 11.1

Alkanes, Alkenes, Isomerism and other Functional Groups SL/HL

1.Which of the following pairs represent members of an homologous series? ;

A. C2H4 and C2H6

B. C2H5Cl and C2H4Cl2

C. CH3OCH3 and CH3CH2OH

D. C3H7COOH and C4H9COOH

2. Which names are correct for the following isomers of C6H14?

2-methylpentane

2ethyl-2-methylpropane

2,3-dimethylbutane

A. I only

B. I and II only

C. I and III only

D. I,II and III

3. How many different structural isomers have the formula C4H9C1?

A. 2

B. 3

C. 4

D. 5

4. How many different isomers have the formula C4H10 ?

A. 1

B. 2

C. 3

D. 4

5. Which formula represents an amide?

A. CH3CH2NH2

B. CH3CH2N(CH3)2

C. H2NCH2CO2H

D. CH3CONH2

6.Which of the following is an amine?

A. CH3CH2NH2

B. CH3CONH2

C. -[CH2CONHCH2CO]n_

D. CH3CH2C ≡ N

7. Give an equation for the complete combustion of methane, CH4. Identify two products formed by the incomplete combustion of methane and identify one harmful effect caused by one of the products.

(i) List three characteristics of an homologous series, and explain the term functional group.

(ii) Draw the four structures of alcohols of formula C4H9OH

8. The plastic PVC, poly(chloroethene), is made from the monomer chloroethene, C2H3C1, by a polymerization reaction.

(i) Draw the structural formula of chloroethene. [1]

(ii) State the type of polymerization reaction that occurs to make poly(chloroethene) and

identify the structural feature needed in the monomer. [2]

(iii) Draw the structure of the repeating unit of poly (chloroethene). [1]

(iv) Explain why monomers are often gases or volatile liquids, whereas polymers are solids. [2]

Topic 11 Organic Chemistry 11.2

Physical Properties of Functional Groups SL/HL

1. When the compounds below are listed in order of decreasing boiling point (highest to lowest) what is the correct order?

1. ethane

A. 4,3,1,2

B. 4,3,2,1

C. 3,4,1,2

D. 2,1,3,4

2. fluoroethane 3. ethanol

4. ethanoic acid

2. Which substance dissolves in water to give a neutral solution?

A. CH3COOH

B. CH3COONa

C. CH3CH2NH2

D. CH3CONH2

3. Which of the following is expected to be a gas at 25° C?

4. Which compound is the most soluble in water?

A. Methane

B Propane

C. Propan-1-ol

D. Pentan-1-ol

5. Which one of the following compounds is optically active?

A. CH3CH2CH2CH2NH2

B. CH3CH2CHCH3

C. CH3CH2NCH2CH3

D. CH3CH2NCH3

CH3

6.Which of the following compounds is optically active?

A. HO - CH2 - COOH

B. H3C - CH - COOH

C. H3C - CH - COOH

CH3

D. CH3

H3C - C - COOH

7.Which compound can exist as optical isomers?

A. H2NCH2COOH

B. CH2C1CH2C1

C. CH3CHBrI

D. HCOOCH3

8. 0.1 mol dm-3 aqueous solutions of these organic compounds were prepared. When these solutions are arranged in order of increasing pH (lowest pH first), what is the correct order?

I. CH3CH2CH2OH

II. CH3CH2CH2NH2

III. CH3CH2COOH

A. I<II<III

B. III<I<II

C. II<III<I

D. III<II<I

9. Statement (S): Solubility of alkanols in water decreases with increase in Mr.

Explanation (E): The relative proportion of the hydrocarbon part in alkanol increases with increasing Mr.

A. Both S and E are true.

B. Both S and E are false.
C. S is true but E is false.

D. S is false but E is true.

10. (a) State and explain the trend in boiling points of the first 10 members of the alkene series. [3]

(b) Explain why the boiling points of ethanol and ethanoic acid are considerably higher than the boiling point of ethanal. [3]

11. Explain why alkanoic acids are more acidic than alkanols. [2]

12. Discuss the factors which affect the boiling points of covalently bonded compounds by reference to the following pairs of organic substances, whose boiling points are given:

• ethane (184 K) and butane (273 K);

• ethane ( 184 K) and bromoethane (311 K);

• bromoethane (311 K) and ethanol (352 K). [6]

Topic 11 Organic Chemistry 11.3

Addition Reactions of Alkenes and Oxidation of Alcohols SL/HL

1. Which chemical is most likely to be a starting material for a common polymer?

A. CH3CH2CH3

B. CH3CH2OH

C. CH3CHCH2

What will be formed when CH2 = CH2 reacts with Br2 in the dark?

A. CH2Br —CH2Br

B. CH3—CHBr2

C. CH2=CHBr + HBr

D. CHBr = CHBr + H2

3. What is the final product formed when ethanol, CH3CH2OH is reacted with acidified potassium dichromate(VI)?

A. ethanal

B. ethane

C. ethanoic acid

D. ethene

4. Which compound will undergo oxidation when treated with acidified potassium dichromate(VI)?

A. CH3CH2CHO

B. CH3COCH3

C. CH3COOH

D. (CH3)3COH

5. Polyunsaturated oils contain many C = C bonds and react with hydrogen to yield fats. Using the simplified structure of an oil provided below, give the formula of the product formed by reacting this oil with excess hydrogen, and identify this type of reaction.

[2]

6. Under certain conditions ethene can be converted to ethanol.

(i) Give a chemical test to identify ethene and state what would be observed.

(ii) Give a balanced equation for the reaction to form ethanol from ethene.

(iii) State the conditions necessary for the reaction in (ii). [4]

7. Propan-1-ol, in the presence of a small amount of oxidising agent, forms compound X, and when refluxed with an excess of oxidising agent, forms compound Y.

(i) Identify a suitable oxidising agent and state the colour change. [2]

(ii) Draw the structural formulas of both compound X and compound Y. [2]

Topic 11 Organic Chemistry 11.4

Condensation Reactions and Condensation Polymerisation SL/HL

1. What is the name of the compound CH3CH2CH2COOCH3 ?

A. Butyl methanoate

B. Methyl butanoate

C. Methyl propanoate

D. Pentanone

From which two chemicals could this compound be synthesised?

A. butanoic acid and pentan-1-ol

B. butanoic acid and butan-1-ol

C. butanal and pentan-1-ol

D. pentanoic acid and butan-1-ol j

3. CH3OH + CH3CH2COOH → CH3CH2COOCH3 + H2O

The forward reaction represented by the equation above is

A. addition.

B. esterification.

C. hydrolysis.

D. neutralisation.

4. Consider the following reaction:

heat

CH3COOH + NH3→ CH3COONH4 → CH3CONH2

What will be the final product if aminoethane (ethylamine) is used instead of NH3 ?

A. CH3CONHCH2CH3

B. CH3CONHCH3

C. CH3CONH 2

D. CH3CONH2CH2CH3

5. When ethanol is warmed with ethanoic acid in the presence of an acid catalyst a new product is formed.

(a) Write the balanced equation for the reaction that takes place using the structural

formulas of the organic reactants and products. [3]

(b) State how the organic product may be distinguished from the reactants and to which
homologous series it belongs. [2]

(d) State and explain how the solubility of the product in water compares with the
solubililty of the two reactants in water. [2]

6. (i) Draw the structural formula of methyl methanoate. State the conditions and the starting
materials for the preparation of methyl methanoate in the laboratory. Write a balanced
chemical equation for the reaction. [5]

(ii) Draw the structural formula of an isomer of methyl methanoate. State two physical
properties and one chemical property that would be different for the two compounds.
State how each of these properties differ for the two compounds. [5]

7 (a) Name the two functional groups attached to the benzene ring in the following compound: [2]

(b) (i) The above compound undergoes polymerisation. Write the structural formula of the

organic product formed when two molecules of this compound react with one another. [2]

(ii) What name is given to the links between the rings in the polymer formed from this

compound? [I]

(iii) Give the name or formula of the other substance that is formed in the polymerisation reaction. [1]

(iv) What type of polymerisation reaction is this? [1]

Topic 11 Organic Chemistry 11.5

Core Material SL/HL

1. Explain why methanol has a much higher boiling point than ethane (Mr = 30). [2]

2. (i) Ethanoic acid reacts with ethanol in the presence of concentrated sulfuric acid and heat
Identify the type of reaction that takes place. Write an equation for the reaction, name
the organic product and draw its structure. [4]

(ii) State and explain the role of sulfuric acid in this reaction. [2]

3 Ethanol may be converted to ethanoic acid.

(i) Identify the reagent needed and state the type of reaction. [2]

(ii) State the colour change observed during the reaction. [1]

4. (i) Explain the term condensation and state the structural features of the monomers
required to form condensation polymers. How does addition polymerisation differ
from condensation polymerisation? [3]

(ii) Terylene is a polymer produced from the polymerisation of the two monomers
ethane- 1,2-diol and benzene-1,4-dicarboxylic acid. State what type of polymer
Terylene is and draw the structural formula of its repeating unit. [3]

5. For each of the following conversions:

(i) ethene → poly(ethene)

(ii) ethanol → ethyl ethanoate

(iii) any 2-aminoacid → a tripeptide

identify the type of reaction, the reagent(s) needed, the condition(s) needed and the structural
formula of the product. [12]

Topic 11 Organic Chemistry

Determination of structure

11.6 HLONLY

1. The low resolution 1H-NMR spectrum shown above could be given by

A. CH3OH.

B. CH3CH2OH.

C. HCHO.

D. HCOOH.

2. Which of the compounds below will show a single peak in its 1H-NMR spectrum?

A. I only

B. III only

C. I and II only

D. I,II and III

3. A compound shows the following spectroscopic results:

mass spectrum; Peaks at 15 and 46 (no peak at 29)

ir spectrum; No peak attributable to -OH

From this information the structure of the compound is most likely

A. CH3OCH3

B. HCOOC2H5

C. C2H5OH

D. HCOOH

4. The mass spectrum of CH3COOC2H5 is not expected to show a major ion peak at which m/e ratio?

A. 88

B. 32

C. 29

D. 15

5. The infrared spectrum of a compound shows a broad absorption band at 3325 cm-1 and another band at 1060 cm-1, but no absorption around 1700 cm-1. Which type of compound is it most likely to be?

A Amine

B. Alkanol

C. Alkanone

D. Alkanoic acid

6. How many different hydrogen signals would be present in the 1H-NMR spectrum of 2-chloropropane, CH3CHClCH3 ?

A. One

B. Two

C. Three

D. Seven

7. How many lines would be expected in the proton NMR spectrum of benzene, C6H6 ?

A. 1

B. 2

C. 6

D. 42

8.How many different environments for hydrogen atoms are present in the 1H-NMR spectrum of the following compound?

(CH3)2CHCH2CH3

A. 3

B. 4

C. 5

D. 9

9. How many lines are present in the 1H-NMR spectrum of C(CH3)4 ?

A. 1

B. 3

C. 4

D. 12

10. X is an organic compound composed of carbon, hydrogen and oxygen, containing 48.63 % carbon and 8.18% hydrogen by mass.

(a) Calculate the empirical formula of X. [4]

(b) The mass spectrum for X is shown below.

(i) Deduce, giving a reason, the molecular formula of X. [2]

(ii) Identify the formulas of the fragment ions with m/z values of 45 and 29. [2]

Using the above spectrum,

(i) explain why X is not a carboxylic acid. [I]

(ii) identify, giving reasons, three bonds that are present in X [3]

(d) Deduce the most likely structural formula of X based on your answers to (b) and (c). State

the name of X and give one use of compounds belonging to this homologous series. [3]

(e) State and explain the number of peaks compound X will show in its low resolution 1H-NMR
spectrum, [2]

(f) State me names of two compounds which could react together to produce X. Identify the type

of reaction and give an equation for the reaction. [4]

Topic 11 Organic Chemistry 11.7

Higher Level Reactions of Alkanes, Alkenes and Alcohols HL ONLY

1. Which is a correct description of a free radical?

A. It is a negatively charged species formed by the homolytic fission of a covalent bond

B. It is a neutral species formed by the heterolytic fission of a covalent bond

C. It has an unpaired electron and is formed by the heterolytic fission of a covalent bond

D. It has an unpaired electron and is formed by the homolytic fission of a covalent bond

2. Which compound reacts by electrophilic substitution?

A. 1-Bromobutane

B. Cyclohexane

C. Methylbenzene

D. Propanone

3 Which of the compounds below is/are more likely to undergo substitution, rather than addition, reactions? I. CH3CHCH2

II. (CH3)3CC1

III. C6H6

A. I only

B. II only

C. I and III only

D. II and III only

4. In which of the following ways does benzene, C6H6, react?

I. Combustion

II. Hydrogenation

III. Substitution

A. I only

B. I and II only

C. I and III only
D. I,II and III

5. Which alkene can be formed by the dehydration of pentan-2-ol?

A. CH2CHCH(CH3)2

B. CH2C(CH3)CH2CH3

C. CH3CHCHCH3

D. CH2CH(CH2)2CH3

6. An organic liquid L has a relative molecular mass of 46. On heating with concentrated H2SO4 at 170 °C, a colourless gas is evolved which decolourises Br2 (aq). What is the organic liquid L?

A. CH3CH2OH

B. CH3OCH3

C. CH3CH=CH2

D. CH3OH

7. Which will be the main product when ethanol reacts with excess concentrated phosphoric acid?

A. Ethene

B. Methoxymethane

C. Ethanoic acid

D. Ethanal

8. Alkanes are often described as having low reactivity, although they do react with halogens.

(i) Explain why alkanes are unreactive. [2]

(ii) The first step in the reaction of propane with bromine can be represented by the equation.