Chemical Reactions: Example Problems

Try to solve these problems before watching the solutions in the screencasts.

Example Problem 1

39.0 g of KO2 reacts at 25°C with CO2 that is kept in a 3.30 L sealed vessel with an original pressure of 6.40 atm. What is the final total pressure of the system after completion of the reaction? Assume the temperature remains constant and that the volume occupied by the solids is negligible.
4KO2 (s) + 2CO2 (g) → 2K2CO3 (s) + 3O2 (g)

Example Problem 2

A reactor is fed 100 mol CH4 and 150 mol O2 per minute. Two reactions take place to form CO2, CH2O, and H2O. Calculate the moles of each component leaving the reactor if all the CH4 reacts and the CO2/CH2O selectivity is 9.0.

Example Problem 3 (optional)

Consider the reaction 4PH3 (g) → P4 (g) + 6H2 (g).

What happens to a container of PH3, P4, and H2 at equilibrium if: we add more PH3; we add more P4; or we decrease the volume at a constant temperature?

Le Chatelier’s Principle