1 Flashcards
(19 cards)
Define rate of reaction
The change in concentration of a reactant or a product in a given time
Factors that affect rate of reaction
Temperature Pressure (when reactants are gasses) Concentration Surface area Catalyst
Definition of activation energy
The minimum energy required to start a reaction by the breaking of bonds
Why do some reactions have high activation energy?
Because alot of energy is required to break the bonds for the reaction to begin
Do all collisions result in reactions?
No, they must have energy equal to or greater than the activation enegry and must collide with the correct orientation.
What does the area under the curve in a Boltzmann distribution represent?
The are under the curve is equal to the total number of molecules in the sample.
What happens to the Boltzmann distribution curve at high temperatures?
The peak moves to the right and down
What is the definition of a catalyst?
A substance that increases the rate of a chemical reaction without being used up in the process
What does a catalyst do to increase rate of reaction?
Decreases the activation energy.
What is a heterogeneous catalyst?
A catalyst that is in a different physical state to the reactants.
What is a homogeneous catalyst?
A catalyst that is in the same physical state to the reactants.
What reaction can exhaust products with a catalytic converted be represented by?
2CO + 2NO = 2CO2 + N2
How do leaded petrols stop catalytic converters working?
They coat the active sites on the surface with layers of lead, preventing them from catalysing the reaction
What are CFCs?
Chlorofluerohydrocarbons
What is a dynamic equilibrium?
It is the equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction
What is Chatelier’s principle?
When a system in dynamic equilibrium is subjected to a change, the position of equilibrium will shift to minimise the change
What is the affect of increasing the temperature in a reversible reaction?
It moves the equilibrium in the endothermic direction
What does increasing the pressure do to a reversible reaction?
Moves the equlibrium to the side with less moles of gas
What effect does adding a catalyst have on an equilibrium?
None, the rate of reaction increases in both directions
