1. A rate is any change that happens over time
7.4 Reaction Rates
A rate is any change that happens over time
A reaction rate is the rate at which reactants change to products over time. ( How fast is it going?)
If collisions occur more frequently, the reaction rate increases↑
There are 5 factors that affect reaction rates…..

2. These are the 5 factors: Temperature Surface area Concentration
Stirring
Catalysts

3. Temperature
Particles that move faster are more likely to collide and therefore, react.
If the number of collisions that produce reactions increases, then the reaction rate increases.
“people in a box”
Batteries
Cooking

4. Surface area
An increase in the surface area increases the exposure of the reactants to one another.
Chocolate milk

5. Concentration
Concentration refers to the number of particles in a given volume
The more reacting particles that are present, the more opportunities there are for collisions of those particles.
“People in a box”
Oxygen test

6. Stirring
Stirring also increases the exposure of the reactant particles to one another.
Stirring will increase the rate of a reaction
Lemonade

7. Catalysts
A catalyst is a substance that affects the reaction without being used up in the reaction
Enzymes – biological (protein) catalysts
MnO2 – our lab used this