Question 1

Paper 2Hard8 marks

Aspirin (acetylsalicylic acid) can be prepared by either of the reactions shown in Figure 1. Use the atom economy equation in the data booklet and the following relative atomic masses: Ar(C)=12.01A_\mathrm{r}(\mathrm C)=12.01 Ar(H)=1.01A_\mathrm{r}(\mathrm H)=1.01 Ar(O)=16.00A_\mathrm{r}(\mathrm O)=16.00 Ar(Cl)=35.45A_\mathrm{r}(\mathrm{Cl})=35.45

Two routes to aspirinRoute I1C(=O)OHOH2-hydroxybenzoic acid(salicylic acid)+1CH3C(=O)OC(=O)CH3ethanoic anhydride1C(=O)OHOC(=O)CH3aspirin (acetylsalicylic acid)+1CH3C(=O)OHethanoic acidRoute II1C(=O)OHOH2-hydroxybenzoic acid(salicylic acid)+1CH3C(=O)Clethanoyl chloride1C(=O)OHOC(=O)CH3aspirin (acetylsalicylic acid)+1H-Clhydrogen chloride
(a)

Calculate the atom economy of Route I, to 3 significant figures.

[2]
(b)

Calculate the atom economy of Route II, to 3 significant figures.

[2]
(c)

For each route, determine the mass of reactant material not incorporated into aspirin, per mole of aspirin formed, on the basis of the balanced reaction. Use your answers to (a) and (b) to assess the claim: “Route II must generate less waste in an industrial process because it has a higher atom economy.”

[4]

More R2.1 How much? The amount of chemical change questions