DP Chemistry (last assessment 2024)
Question 19M.3.sl.TZ1.a(ii)
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.3.sl.TZ1.a(ii) |
| Level | sl | Paper | 3 | Time zone | TZ1 |
| Command term | Determine | Question number | a(ii) | Adapted from | N/A |
a(ii).
[Maximum mark: 2]
19M.3.sl.TZ1.a(ii)
Mild heartburn is treated with antacids such as calcium carbonate.
Determine the volume of CO2 (g), in dm3, produced at STP, when 1.00 g of CaCO3 (s) reacts completely with stomach acid.
Mr CaCO3 = 100.09
[2]
Markscheme
n CaCO3 = « =» 0.00999 «mol» [✔]
volume CO2 = «0.00999 mol × 22.7 dm3 mol–1 = » 0.227 «dm3» [✔]
Note: Accept 0.224 «dm3» if 22.4 dm3 mol–1 is used as molar volume.
Award [2] for correct answer.
Examiners report
It was encouraging that over half the students were able to calculate the volume of gas produced from a given mass of calcium carbonate.
