Rate Of Reaction (T4) Flashcards
What are the formulas for rates of reaction?
Rate of reaction = amount of reactant used / time
OR
amount of product formed / time
Describe collision theory..
For reactions to occur the atoms need to not only be able to run into each other, but also have a certain level of energy.
The theory dictates that the higher the number of reacting atoms there are, and the higher the energy they possess, the more rapid the reaction should be.
What does collision theory state about temperature?
The higher the temperature of an atom, the more movement it has.
If collision theory is correct, we should see some reactions not happening or happening very slowly if the temperature is below a certain point.
This means that reactions require a certain amount of energy to ‘get started’ and if the atoms have enough energy they reach a threshold above which a reaction can occur.
How does concentration affect the rate of reaction?
In an aqueous solution, the more atoms there are of the two reactants, the more likely they are to bump into each other and react.
Concentration requires atoms of both reactants. If the concentration of both reactants if very high then it is more than likely that the atoms of the reactants will encounter each other and react.
This tends to explain the nature of reactions - if a reaction starts in a liquid then it may start very quickly, with the atoms reacting with each other to form a new substance.
But sooner or later the amount of unreacted atoms within the mixture will decrease, slowing the reaction further and further.
How does pressure affect the rate of reaction?
If the reaction is between gases then increasing the pressure will also increase the energy and the number of times that the atoms hit each other.
This will increase the speed of reactions.
Reducing the pressure will reduce the number of collisions, decreasing them since fewer atoms are there to impact each other.
