Question 22M.2.hl.TZ1.c(iii)
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.2.hl.TZ1.c(iii) |
| Level | hl | Paper | 2 | Time zone | TZ1 |
| Command term | Suggest | Question number | c(iii) | Adapted from | N/A |
Magnesium is a reactive metal often found in alloys.
A graph of the volume of gas produced by reacting magnesium with a large excess of 1 mol dm–3 hydrochloric acid is shown.
Carbonates also react with HCl and the rate can be determined by graphing the mass loss. Suggest why this method is less suitable for the reaction of Mg with HCl.
[1]
«relative/percentage» decrease in mass is «too» small/«much» less ✔
Accept “«relative/percentage» uncertainty in mass loss «too» great”. OR “density/molar mass of H2 is «much» less than CO2”.
Poorly done; many candidates did not grasp the question and answer it appropriately. Candidates generally did not realize that decrease in mass (due to H2(g) as a product for the reaction of Mg with HCl) is «too» small/«much» less compared to that of CO2(g) from the reaction of carbonates with HCl.
