Question 1

What is activation energy?

Accepted Answer

Activation energy (Ea) is the minimum energy required for a chemical reaction to occur. It represents the energy barrier that reactants must overcome to form products. Higher Ea means slower reactions.

Question 2

What is the Arrhenius equation?

Accepted Answer

The Arrhenius equation is k = A·exp(-Ea/RT), where k is the rate constant, A is the pre-exponential factor, Ea is activation energy, R is the gas constant (8.314 J/(mol·K)), and T is temperature in Kelvin.

Question 3

How does a catalyst affect activation energy?

Accepted Answer

A catalyst lowers the activation energy by providing an alternative reaction pathway. This speeds up the reaction without being consumed. The catalyst does not change ΔG or the equilibrium position.

Question 4

What are typical activation energy values?

Accepted Answer

Most chemical reactions have Ea between 40-200 kJ/mol. Enzyme-catalyzed reactions may have Ea as low as 10-30 kJ/mol. Very fast reactions (like explosions) have low Ea, while slow reactions (like rusting) have high Ea.

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