DP Chemistry (last assessment 2024)
Question 19M.3.sl.TZ1.a(i)
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.3.sl.TZ1.a(i) |
| Level | sl | Paper | 3 | Time zone | TZ1 |
| Command term | Formulate | Question number | a(i) | Adapted from | N/A |
a(i).
[Maximum mark: 1]
19M.3.sl.TZ1.a(i)
Mild heartburn is treated with antacids such as calcium carbonate.
Formulate an equation for the neutralization of stomach acid with calcium carbonate, CaCO3 (s).
[1]
Markscheme
CaCO3 (s) + 2HCl (aq) → CO2 (g) + CaCl2 (aq) + H2O (l) [✔]
Note: Accept balanced ionic equations involving “H+” or “H3O+”.
Do not accept “H2CO3”.
Examiners report
About two-thirds of the candidates could write an equation for the reaction of calcium carbonate with an acid. It was refreshing to find that “H2CO3” was only rarely encountered as a product.
