Rates of Reaction

Kinetics

movement of molecules; the average kinetic energy of molecules is directly proportional to temperature in Kelvin.

Necessities for reaction after a collision between molecules

1. Enough to break bonds in the reactants

2. The molecules must collide in a specific orientation (alignment) that brings the reactive parts of the molecules together to form new bonds

Activation energy

the minimum energy needed for a reaction to occur; the difference in energy between the transition state and the energy of reactions

transition state

short-lived complex where existing bonds are breaking and new bonds are forming; highest energy point of a reaction.

reaction rate

the change in the concentration of products over time or the change in the concentration of reactants over time; measures how fast the reaction occurs

experimentally

reaction rate can only be determined _______.

rate law

expresses the relationship between the rate of chemical reaction and the concentration of the reactants; rate = K[A][B].

Activation energy

the rate of a reaction depends on its _______ (larger = slower reaction, smaller = faster reaction)

Changing rate of a reaction

1. Reactant concentration: a higher concentration means more particles, which leads to more collisions

2. Temperature: higher temperature equals more kinetic energy, which means a higher velocity and results in more collisions with sufficient energy to overcome the Ea barricade

3. presence of a catalyst: increases rate of reaction by lowering the activation energy; provides a lower energy pathway for the reaction

4. Increasing the surface area by decreasing the particle size results in more collisions

5. physical state of reactants (the more movement, the faster the reaction rate)