Unit 2 Section 3 Reaction Rates Flashcards
What is activation energy?
The minimum amount of energy kinetic energy particles need to react. This is needed to break the bonds to start the reaction.
When will a reaction between 2 moving particles take place?
They have to collide in the right direction.
They have to have a minimum amount of energy.
What is a maxwell Boltzmann distribution?
It shows the number of molecules that have a certain amount of energy. It starts at (0,0) as no particles will have 0 energy and it will have positive skew as a few particles will have a lot of energy.
When the temperature of something is increased, what will this do to the maxwell Boltzmann distribution?
It will move it towards the right meaning a greater area under the graph will be above the activation energy.
How do catalysts work?
They lower the activation energy by providing a different way for the bonds to be broken and remade.
How does increasing concentration speed up a reaction?
Increasing the concentration or pressure, means they are more particles and they are closer together, meaning more collisions.
How does increasing surface area speed up a reaction?
It gives the particles more of a chance to react with each other.
What is the definition of a catalyst?
They increase the rate of a reaction by providing an alternative reaction pathway with a lower activation energy. It will remain chemically unchanged. They often take part in the reaction but are remade at the end.
What is a homogeneous catalyst?
One that must be in the same state as that of the reactants. If there are gases, it must be a gas. If they are aqueous, it must be aqueous.
How do homogeneous catalysts work?
It forms intermediate compounds from the reactants which then form the products.
The energy needed to form the intermediates and then the products uses less energy then form going straight from reactants to products.
On the enthalpy profile diagram, there will be 2 humps.
How can the rate of a reaction be measured?
Measure the volume of gas produced.
Measure the decreasing mass on a scale as gas is produced.
See how quickly a precipitate forms by looking at a cross through a solution as it goes cloudy. It is however subjective and the original
What is dynamic equilibrium?
When the rate of the forward reaction is the same as the rate of the backward reaction. It can only happen in a closed system.
What affect do catalysts have on equilibrium?
They don’t have any affect. They can’t increase yelled but it does mean yield is reached faster.
How can changing conditions affect the position of equilibrium?
Increase the concentration of the reactants and it goes to the right to make more products.
Increase the pressure and it will move to the side where there are less moles.
If you increase the temp it will move in the endothermic direction to try and reduce it. The converse is also true.
On a graph of the maxwell Boltzmann distribution what are on the axes?
No. off particles on the y axis.
Energy of particles on the x axis.
