1. Molecules X, Y and Z all have the same number of carbon atoms.

What is the order of melting points, from highest to lowest, for these three molecules?
A. Y, X, Z
B. Y, Z, X
C. Z, X, Y
D. Z, Y, X

Solution
2. Consider the following statements about coenzymes.
I. Coenzymes assist enzymes to catalyse a reaction.
II. Coenzymes bind loosely to the active site of an enzyme.
III. Coenzymes act as carriers in the transfer of electrons and atoms. Which of the statements above are correct?
A. I and II only
B. I and III only
C. II and III only
D. I, II and III drones are endothermic.

Solution
3. Which molecule can exist as both a cis and a trans isomer?
A. CH₂CBrCl
B. CH₃CHBrCl
C. CH₃CHCHCl
D. (CH₃)₂CCCl₂

Solution

4. Compare omega-6 fatty acids with saturated fatty acids containing the same number of carbon atoms. Which one of the following statements is correct? Omega-6 fatty acids
A. have lower densities than saturated fatty acids.
B. have higher melting points than saturated fatty acids.
C. have more hydrogen atoms than saturated fatty acids.
D. undergo substitution reactions more readily than saturated fatty acids.

Solution

5. Which one of the following statements about denaturation is correct? Denaturation
A. can only be caused by changes in temperature or the addition of acids.
B. causes the reversible change of a protein’s shape.
C. hydrolyses the primary structure of a protein.
D. alters the secondary structure of a protein.

Solution

6. Which one of the following is the semi-structural formula of 2-methylpent-1-ene?
A. (CH₃)₂CCHCH₂CH₃
B. (CH₃)₂CHCH₂CHCH₂
C. CH₂C(CH₃)CH₂CH₂CH₃
D. CH₂CHCH(CH₃)CH₂CH₃

Solution

6. The diagram below shows a reaction pathway starting with but-1-ene.

a. But-1-ene can react with water vapour at 300 °C with
H₃PO₄(s) as a catalyst to produce two different products, Compound Q and Compound R. Only Compound R can react to produce butanoic acid.
i. Name the type of reaction that forms Compound Q and Compound R from but-1-ene.
ii. Give the IUPAC name of Compound Q in the box provided on the diagram above.
b. As shown in the diagram, compound R can oxidise completely with acidified potassium dichromate solution,
H⁺(aq)/Cr₂O₇^2-(aq), to form butanoic acid. Compound R can also undergo incomplete oxidation to form Compound T. Draw the structural formula of Compound T in the space below.
c. Under certain conditions, butanoic acid reacts with ethanamine to produce Compound S. Draw the skeletal formula for Compound S in the box provided on the diagram.
d. Butanoic acid can also react with ethanol in the presence of a suitable catalyst to produce an ester. The molar mass of the ester produced is 116.0 g mol^-1. Calculate the atom economy for this reaction.

Solution