C6 - Energy Changes Flashcards
What is an exothermic reaction?
(thermal) energy is released from the reaction.
What happens to the temperature of a reaction mixture after an exothermic reaction?
The temperature of the reaction mixture goes up (it feels hot).
What is an endothermic reactions?
(thermal) energy is taken into the reaction.
What happens to the temperature of a reaction mixture after an endothermic reaction?
The temperature of the reaction mixture decreases (it feels cold).
What are the SI for energy?
Joules (J)
What is activation energy?
The minimum amount of energy required to start a reaction.
What is bond breaking?
Bonds in the reactants are broken during the reaction.
What is bond making?
Bonds in the products are made during the reaction.
What direction do arrows point in an endothermic reaction?
Up
What direction do arrows point in an exothermic reaction?
Down
Where is the overall energy change measured from?
The reactants to the products.
What is on the y-axis of an exo/endothermic reaction?
Energy.
What is on the x-axis of an exo/endothermic reaction?
The progress of reaction.
What is the formula for energy change?
products - reactants
Name two exothermic reactions.
Neutralisation and Displacement.
What type of reaction is Salt Dissolving and Precipitation?
Could be endo or exo depending on the salt and other factors.
What is the difference between a chemical reaction and a physical process?
In a chemical reaction a new chemical is made and in a physical process no new chemical is formed.
What does OIL RIG stand for?
Oxidation
Is
Loss
Reduction
Is
Gain
What must happen for a reaction to happen?
A successful collision.
What is the rate of reaction?
The number of successful collisions per second.
What are five factors that affect the rate of reaction?
Temperature
Concentration
Surface Area aka particle size
Pressure
Catalyst
How does concentration affect the rate of reaction?
Higher concentration = higher frequency, energy stays the same = higher rate of reaction
How does pressure affect the rate of reaction?
Increased pressure = higher frequency, energy stays the same = higher rate of reaction
How does surface area affect the rate of reaction?
Increased surface area = higher frequency, energy stays the same = higher rate of reaction
How does temperature affect the rate of reaction?
Increased temperature = higher frequency, higher energy = higher rate of reaction
How does a catalyst affect the rate of reaction? [4]
With a catalyst:
- activation energy is lower
- frequency is increased
- energy stays the same
- higher rate of reaction
What is a neutralisation reaction?
Acis + Base
