The Rate And Extent Of Chemical Change Flashcards
How do you calculate the mean rate of reaction
Quantity of reaction used or formed/time taken
How can the quantity of reactant or product to be measured
Mass in grams
volume in cm³
The steeper the slope the faster
The reaction
Which factors affect the rate of chemical reactions
The concentration of reactants in solution
the pressure of reacting gases
the surface area of solid reactants
the temperature
presence of catalyst
What is the collision theory
Chemical reactions can only take place when the reacting particles collide with each other. the collision must have a significant energy
What is the rate of a chemical reaction determined by
The frequency of successful collisions
What does frequency mean
The number of successful collision per second
What is the minimum amount of energy that particles must have to react called
Activation energy
A student increases the concentration of reactants in a solution what happens to the pressure and surface area
The pressure of reacting gases and the surface area of a solid reactants increases the frequency of collisions and increases the rate of reaction
Temperature is increased what happens to the frequency
The frequency of collisions increase and makes the conditions more energetics and so increases the rate of reaction
What is a hypothesis
It’s a proposal that could explain a fact or an observation
(In science a hypothesis must be testable)
Sulfur makes the solution go cloudy what is this called
Cloudiness turbidity 
What’s the use of catalysts
Catalysts change the rate of chemical reactions but are not used up during the reaction
What do enzymes act as
Catalyst in biological systems
What does a catalyst do
A Catalyst increases the rate of reaction by providing different pathway for the reaction that has lower activation rate. Different reactions need different catalyst
In some chemical reactions the product can react to produce the original reactants what is this called
Reversible reaction
When is the equilibrium reached
When the forward and reverse reactions occur at the same rate
What does a reversible reaction prevent
The escape of reactants and products
If the concentration of a product decreases what happens to the reactants
More reactants will react until equilibrium is reached again 
If the concentration of reactants is increased what happens to the products
More products will be formed until equilibrium is reached again 
What is the effect of changing conditions on equilibrium
If a system is at equilibrium and a change is made to the conditions then the system will respond to counteract the change
What do scientists call the effect of changing conditions on a system at equilibrium
Le Chatelier’s Principle
What does the relative amount of all the reactants and products at equilibrium depend on
The conditions of reaction
What happens if the concentration of the reactants or products is changed
The system is no longer at equilibrium and the concentrations of all the substances will need to change until equilibrium is reached again
