DP Chemistry (last assessment 2024)
Question 18N.3.sl.TZ0.b
| Date | November 2018 | Marks available | [Maximum mark: 1] | Reference code | 18N.3.sl.TZ0.b |
| Level | sl | Paper | 3 | Time zone | TZ0 |
| Command term | State | Question number | b | Adapted from | N/A |
b.
[Maximum mark: 1]
18N.3.sl.TZ0.b
Buffer systems control pH in the body.
State the equation for the reaction of calcium carbonate, the active ingredient in some antacids, with stomach acid.
[1]
Markscheme
CaCO3 (s) + 2HCl (aq) → CaCl2 (aq) + H2O (l) + CO2 (g)
OR
CaCO3 (s) + 2H+ (aq) → Ca2+ (aq) + H2O (l) + CO2 (g) ✔
