C2.5 Chemical Reactions Flashcards
Define Exothermic
Reaction that releases heat energy
Endothermic
Reaction that takes heat energy in
Describe the connection of exothermic and bonds
Making of bonds are exothermic
Describe the connection of endothermic and bonds
Breaking of bonds are endothermic
What is overall heat energy that changes for a reaction?
Exothermic if more heat energy is released making bonds in products that’s required to break bonds in reactants
Endothermic if less heat energy is released
What is the rate of a chemical reaction?
The speed at which a chemical reaction takes place
Describe the effects the rate of reaction
Temperature - the higher the temperature of reactants, the faster the reaction
Concentration- The higher the concentration, the more reactant particles there are
Surface Area - Increasing the surface area of a solid increases the frequency of collisions which increases rate
How do reactions occur when particles collide and explain how rates of reaction are increased by increasing the frequency
For a reaction to occur, particles of reacting substances must collide
Rate of any reaction will increase if particles collide more frequently (more often = faster reaction)
Collision must also have enough energy to break bonds in reactants
Most collisions don’t have enough energy to start the reaction - rate of reaction increase if there’s more high energy collisions
Demonstrate not all collisions lead to a reaction, especially if particles collide with low energy
However, not all collisions lead to a reaction, especially if particles collide with low energy
What is a catalyst?
A substance that speeds up the rate of a reaction without being used up
What do Catalytic Converters have in cars?
Have a high surface area to increase the rate of reaction of carbon monoxide and unburnt fuel from exhaust gases with oxygen from air to produce Carbon Dioxide and Water
How does Catalytic Converters work best?
At high temperatures
