C6 - Rate and Extent of Chemical Change Flashcards
What are the 2 definitions of
the rate of a chemical reaction?
The rate of a chemical reaction is…
…the amount of product formed per
second.
…the amount of reactant used up per
second
How do you find the rate of reaction from a graph with a curved line?
1 - Draw a tangent to the line at the time
You want to find out.
2 - Calculate the gradient of the tangent
Identify 5 things that increase
the rate of reaction.
1 – Temperature
2 – Pressure
3 – Surface area
4 – Concentration
5 - Catalyst
How does a catalyst increase the
rate of reaction?
A catalyst provides a different
pathway for the reaction that has a
lower activation energy. The
catalyst is not used up in the
reaction
What is a reversible reaction?
A reversible reaction is one in which
the products can react together to
make the original reactants again.
If the forward reaction gives out 2000kJ of energy to the surroundings (exothermic) what will happen when the backwards reaction takes place?
If the forward reaction is exothermic
then the backwards reaction will be
endothermic. It will take in the same
amount of energy as was given out
What does it mean when a
chemical reaction has reached
equilibrium?
At equilibrium, the rate of the forward
reaction equals the rate of the
backwards reaction.
What is Le Chatelier’s Principle?
Le Chatelier’s Principle states that…
…When a change in conditions is
introduced to a system at equilibrium,
the equilibrium shifts so as to cancel
out the change
If you increase the pressure of
a reaction mixture at equilibrium
what will happen?
The equilibrium will shift to make less
particles.
If you increase the temperature
of a reaction mixture at equilibrium
what will happen?
The equilibrium will shift to
reduce the temperature. It will
favour the endothermic reaction.
