Reaction Rates & Collision Theory

Collision Theory In order for a chemical reaction to take place effective collisions must occur between reactants.

AND the molecules must be in the Collisions are only effective if they have enough kinetic energy to overcome the activation energy AND the molecules must be in the proper orientation

5 factors that determine the rate (speed) of reaction

1.) Nature of the Reactants Ionic reactions happen faster than covalent Solutions(aq) & liquids(l) react faster than solids(s)

2.) Temperature increase in temperature increases the rate chemical reactions WHY? the KE of the particles increases, and effective collisions are going to happen more often

3.) Concentration of Reactants

Increasing pressure of GAS Squeezes the molecules closer together and increases the concentration. Molecules closer together increases the number of effective collisions.

but you can increase its surface area Sometimes you can’t change the concentration of the substance but you can increase its surface area

4.) Increasing Surface Area Smaller particle size allows more of the reactant to be exposed . . . and therefore ??????

Enzymes are biological catalysts 5.) Adding a Catalyst A catalyst is a substance that speeds up a chemical reaction without being changed itself. Enzymes are biological catalysts

do not change Adding a catalyst decreases the activation E Energy Initial E and final E do not change Energy

THE END !!!!!!