Chapter 10 - Reaction rates and Equiillibrium Flashcards
What is rate of reaction?
How fast a reactant is being used up or how fast a product is being formed
How can rate of reaction be changed?
Concentration
Temperature
Catalysts
Surface area of solid reactants
Pressure of gases
What is collision theory?
Two reacting particles must collide effectively for a reaction to occur
What conditions are required for particles to collide successfully?
Particles collide with correct orientation
Particles have sufficient energy to overcome activation energy
How does increasing the concentration of a reactant affect the rate of reaction?
Rate of the forward reaction increases
So more product is produced
Increased concentration means more particles in the same volume
So particles collide more frequently so there will be more effective collisions
How does increasing the pressure of gas affect the rate of reaction?
Concentration of gas moles increases as the same number of gas moles occupies a smaller volume
Gas molecules are closer together so will collide more frequently and have more successful collisions
How can the progress of a reaction be followed?
Monitoring the removal of reactant (decreasing concentration)
Monitoring the formation of a product (increasing concentration)
How can progress of reaction be followed with reactions that produce gas?
Monitoring volume of gas produced at regular time intervals
Monitoring loss of mass with an electronic balance
How can rate of reaction be calculated from a graph measuring mass loss?
Plot mass lost against time
Draw tangent on the curve at the time you want to know the rate of reaction
Rate of reaction is the gradient
What does a catalyst do?
Speeds up the rate of reaction without undergoing a permanent change
Not used up in reaction
Will react with a reactant to form an intermediate
Catalyst is regenerated
Provides and alternate reaction pathway that lowers activation energy
What is an intermediate?
A species formed during a reaction that reacts further and is not present in the final products
What is a homogeneous catalyst?
Same physical state as the reactants
What is a heterogeneous catalyst?
Different physical state from the reactants
Usually a solid catalysing a gas reaction
Why are catalysts important?
