Calculate the amounts, in mol, of each reactant.

Calculate, in g, the theoretical yield of aspirin.

State two techniques which could be used to confirm the identity of aspirin.

State how aspirin can be converted to water-soluble aspirin.

Compare, giving a reason, the bioavailability of soluble aspirin with aspirin.

n(salicylic acid) = «$\frac{2.65\text{ g}}{138.13\text{ g}\text{mo}{\text{l}}^{-1}}$» 0.0192 «mol»

AND

n(ethanoic anhydride) = «$\frac{2.51\text{ g}}{102.10\text{ g}\text{mo}{\text{l}}^{-1}}$» 0.0246 «mol»

[1 mark]

«mass = 0.0192 mol x 180.17 g$$mol^–1 =» 3.46 «g»

Award ECF mark only if limiting reagent determined in (i) has been used.

[1 mark]

Any two of:

melting point

mass spectrometry/MS

high-performance liquid chromatography/HPLC

NMR/nuclear magnetic resonance

X-ray crystallography

elemental analysis «for elemental percent composition»

Accept “spectroscopy” instead of “spectrometry” where mentioned but not “spectrum”.

Accept “infra-red spectroscopy/IR” OR “ultraviolet «-visible» spectroscopy/UV/UV-Vis”.

Do not accept “gas chromatography/GC”.

Accept “thin-layer chromatography/TLC” as an alternative to “HPLC”.

[2 marks]

react with NaOH

Accept “NaHCO₃” or “Na₂CO₃” instead of “NaOH”.

Accept chemical equation OR name for reagent used.

[1 mark]

«marginally» higher AND increase rate of dispersion
OR
«marginally» higher AND increase absorption in mouth/stomach «mucosa»
OR
«approximately the» same AND ionic salt reacts with HCl/acid in stomach to produce aspirin again

Do not accept “«marginally» higher AND greater solubility in blood”.

[1 mark]