| Date | May 2016 | Marks available | 3 | Reference code | 16M.3.sl.TZ0.14 |
| Level | SL | Paper | 3 | Time zone | TZ0 |
| Command term | Formulate and Explain | Question number | 14 | Adapted from | N/A |
Question
Atmospheric carbon dioxide and aqueous carbon dioxide in the oceans form a heterogeneous equilibrium.
Explain the effect of increasing concentrations of atmospheric carbon dioxide on the pH of the oceans, including an equation in your answer.
Markscheme
CO2(g)+H2O(l) 
H+(aq)+HCO3-(aq)
OR
CO2(g)CO2(aq) AND CO2(aq)+H2O(l)H+(aq)+HCO3-(aq)
«increasing [CO2]» shifts equilibrium/reaction to right
pH decreases
Accept “H2CO3 (aq)” for “CO2 (aq) + H2O(l)”.
Examiners report
[N/A]
