Rate Of Reaction Flashcards
What does the gradient of a graph showing the rate of reaction represent
The rate of reaction
When the gradient is zero what does that tell about the reaction
The reaction has stopped as all the reactants are used up
How do you calculate the mean rate of reaction
Quantity of product formed / Time taken
How do you calculate the rate of reaction at a given point
By drawing a tangent at the specific point
How do you calculate the gradient (h)
Change in Y / Change in X
What is collision theory
Chemical reactions can only take place when the reacting particles collide with each other, the collisions must have sufficient energy
What is the rate of reaction determined by
The frequency of successful collisions
What does increasing the concentration do to the rate of reaction
It increases the rate of reaction because there are more particles to react with
What’s the relationship between the rate of reaction and concentration
The rate is proportional to the concentration
What is meant by the term frequency
The number of successful collisions per second
What part of the solid can particles react with
The surface of the solid
What’s the effect of increasing the surface area on the rate of reaction
It increases the number of collisions per second so the rate of reaction increases
How do you increase the surface area to volume ratio
By decreasing the size of the solids
What is required for there to be a successful collision
When collisions overcome the activation energy
What does increasing the temperature do to the rate of reaction
Increase the rate of reaction
Explain why increasing the temperature increases the rate of reaction
The particles have more energy so the frequency of collisions increases because more particles can overcome the activation energy barrier and collide successfully
What is the relationship between the rate of reaction and temperature
They are proportional
What is the role of catalysts
They increase the rate of reaction but aren’t used up during the reaction
Why do catalysts increase the rate of reaction
Because they lower the activation energy by offering an alternative pathway for the particles
What are reversible reactions
When products can react to reform the original reactants
If a reversible reaction is exothermic in one direction what is it in the opposite direction
Endothermic
What is equilibrium
The point where the forward and reverse reactions take place at exactly the same rate
What is Le Chatliers principal
If a system is at equilibrium and a change is made to the conditions then the system responds to counteract the change
What happens when you increase the temperature of reversible reaction
The equilibrium shift to reduce the temperature
What does the pressure of a gas depend on
The number of molecules
What happens if the pressure increases on a reversible reaction at equilibrium
The position of the equilibrium shift to the side of the smaller number of molecules
