Question
Bromine, \(Br_2\) (l), and methanoic acid, HCOOH(aq), react in the presence of sulfuric acid.
\(Br_2 (l) + HCOOH(aq) → 2HBr(aq) + CO_2 (g)\)
(a) Suggest an experimental method that could be used to determine the rate of reaction.
(b) The sulfuric acid is a catalyst in this reaction. Explain how a catalyst increases the reaction rate.
(c) Methanoic acid can react with ethanol to produce an ester. Draw the full structural formula of the organic product and state its name.
Structural formula:
Name:
(d) (i) Write the equation for the complete combustion of ethanol.
(ii) Determine the enthalpy change for the combustion of ethanol, in kJ \(mol^{−1}\), using section 11 of the data booklet.
(e) Bromine also reacts with but-2-ene.
(i) Identify the type of reaction.
(ii) Predict the structural formula of the reaction product.
(iii) Draw the structure of a section of a polymer formed from three monomers of but-2-ene.
Answer/Explanation
Answer:
(a) «measure change in»
mass
OR
pressure
OR
volume of gas/\(CO_2\) produced
OR
«intensity of» colour
OR
«electrical» conductivity
OR
pH
with time
(b) provides an alternative reaction pathway AND lower activation energy/\(E_a\)
larger fraction/number of molecules with E ≥ \(E_a\)/enough energy «for a successful
collision»
(c) Structural formula:
Name:
ethyl methanoate
(d) (i) \(CH_3CH_2OH(l) + 3O_2(g) → 2CO_2(g) + 3H_2O(g)\)
(ii) «bond breaking»
1 C-C + 5 C-H + 1 C-O + 1 O-H + 3 O=O / 346 + 5(414) + 358 + 463 +3(498) /
4731 «kJ»
«bond forming»
4 C=O + 6 O-H / 4(804) + 6(463) / 5994 «kJ»
∆H «= 4731– 5994» = −1263 «kJ \(mol^{−1}\) »
(e) (i) «electrophilic» addition/\(A_E\)
(ii) \(CH_3CHBrCHBrCH_3\)
(iii) 
Question
Alkanes form a homologous series.
(a) (i) Outline the meaning of homologous series.
(ii) State the preferred IUPAC name for the following compounds.
(iii) But-2-ene can be polymerized. Draw a section of the resulting polymer showing two repeating units.
Answer/Explanation
Answer:
(a) (i) compounds of the same family AND general formula
OR
compounds of the same family AND differ by a common structural unit/\(CH_2\)
(ii) 
(iii) 