Rate of Reaction & Reversible Reactions Flashcards
What is the speed of a reaction called?
The rate.
What are the factors that increase the rate of reaction?
Catalyst, Concentration/Pressure, Surface Area and Temperature.
What is a Catalyst?
A substance that increases the speed of a reaction and cannot be used up.
Are reversible reactions endothermic or exothermic?
They are endothermic in one way an exothermic in the other.
How can reaction rates be changed?
When the reaction conditions change.
What is Collision Theory?
Collision theory says that a reaction will only take place when particles collide with sufficient energy.
What is activation energy?
The smallest amount of energy needed to cause a reaction.
What is the rate of a reaction?
How fast the reactants are changed into products.
What must particle do in order to react?
Collide with sufficient energy.
What does this (⇌) symbol mean?
The reaction is reversible
What is a reversible reaction?
A reaction that can be reversed.
Here is a reaction: A + B ⇌ C + D
a) What type of reaction is this?
b) What is the reaction of A + B called?
c) What is the reaction of C + D called?
a) Reversible reaction
b) forward reaction
c) backward reaction
What is Equilibrium?
The point at which the rates of the forward and backwards reactions (in reversible reactions) are the same.
How do Catalysts speed up a chemical reaction?
Catalysts work by providing a different pathway for a reaction. The new pathway has a lower activation energy, so less energy is needed for the reaction to happen.
What is the equation for mean rate of reaction (product formed)?
mean = product formed / time
What is the equation for mean rate of reaction (reactant used)?
mean = reactant used / time
How does the concentration/pressure of a reactant affect the rate of reaction?
The higher the concentration/pressure of a reactant is, the more particles will be able to collide. Using collision theory, this means that the rate of reaction will increase.
On a graph, what does a steeper line show?
The rate increasing.
On a graph, what does a flat line show?
The reaction has finished/stopped.
What is the rate of a reaction determined by (collision theory)
The frequency of successful collisions.
How does the surface area of a reactant increase the rate?
When reacting a solid with a solution/gas, the particles of the solution/gas can only react (collide) with particles on the surface of the solid. Increasing the surface area of the solid will provide a larger surface for the collisions to take place.
What is Le Chatelier’s Principle?
If a system at equilibrium is subjected to a change, the system will adjust to counteract that change.
Explain what is meant by; ‘Equilibrium lies to the right’
The concentration of products is greater than that of reactants.
What are three factors that the position of equilibrium depends on?
- Temperature
- Pressure
- Concentration.
