Unit B Section 4.3 Flashcards
The four factors that can affect the rate of a chemical reaction are:
- the presence of a catalyst
- the concentration of the reactants
- the temperature of the reactants
- the surface area of the reactants
What are Catalysts?
Catalysts are substances that help a reaction proceed faster
-but they are not consumed during
the reaction
-Chemical reactions involving catalysts can be found in both living and non-living things.
Example of a catalyst?
enzyme
Without enzymes, many reactions would require much higher temperatures—a situation that would be deadly to the human body
For example, one product of reactions in cells is hydrogen peroxide (H2O2
(poisonous)
An enzyme called catalase, which is found in
many different types of animal and plant cells speed up the breakdown of hydrogen peroxide into harmless oxygen and water
Fuel cells use a platinum catalyst to generate electricity from the reaction of hydrogen and oxygen. These cells can now be found in
cars and other devices
Concentration:
- The greater the concentration of the reactants, the faster the reaction
- The increased concentration of the reactants means that there are more atoms of each reactant available to react.
- For example, adding more aluminum to a copper(II) chloride solution will cause the reaction between the two substances to proceed faster.
Temperature:
-The more heat added to the reactants, the faster the reaction.
-The added heat
causes the atoms of each reactant to move faster, which increases the chances of their colliding with each other.
-For example, you could heat the copper(II) chloride solution to make the reaction proceed more quickly.
Surface area:
-The greater surface area of the reactants means that more area is available for reaction.
- In the copper(II) chloride and aluminum example, cutting the aluminum foil into tiny pieces would
increase the surface area, causing the reaction to proceed faster.
