Practice Activation Energy in Chemistry
Use these practice problems to test your method after reviewing the concept explanation and worked examples.
Quick Recap
The minimum kinetic energy that reactant particles must possess upon collision in order to break existing bonds and initiate a chemical reaction, represented as the energy barrier on a reaction energy diagram.
The 'hill' reactants must climb over before the reaction can proceed.
Example 1
easyExplain why a match must be struck before it ignites, even though combustion is exothermic.
Example 2
mediumOn an energy diagram, Reaction A has E_a = 50\,\text{kJ/mol} and Reaction B has E_a = 120\,\text{kJ/mol}. Both occur at the same temperature. Which reaction is faster and why?
Example 3
easyDoes a catalyst change the activation energy of a reaction? How?
Example 4
mediumPaper burns exothermically, but a sheet of paper can sit at room temperature for days without catching fire. Why?