Chemical Kinetics

What is Chemical Kinetics?

The branch of chemistry that deals with the study of reaction rates, the factors affecting them, and the mechanism by which reactions proceed.

Define the Rate of a Reaction.

The change in concentration of any one of the reactants or products per unit time. Its unit is typically mol\ L^{-1}\ s^{-1} or M\ s^{-1} (for solution phase reactions) or atm\ s^{-1} (for gaseous reactions).

Differentiate between Average and Instantaneous Rate of Reaction.

1. Average Rate: The change in concentration over a measurable time interval. Expressed as \frac{\Delta[Reactant]}{\Delta t} or \frac{\Delta[Product]}{\Delta t}.
2. Instantaneous Rate: The rate of reaction at a particular instant in time. Expressed as \frac{d[Reactant]}{dt} or \frac{d[Product]}{dt}.

List the major factors affecting the Rate of a Reaction.

1. Concentration of Reactants: Generally, reaction rate increases with increasing concentration.
2. Temperature: Rate of reaction usually increases with increasing temperature (often doubles for every 10^\circ C rise).
3. Catalyst: A substance that alters the rate of a reaction without being consumed, typically by lowering the activation energy.
4. Surface Area: For reactions involving solids, increasing surface area increases the reaction rate.
5. Pressure: For gaseous reactants, increasing pressure (which increases concentration) increases the reaction rate.