Chem 5 - Kinetics, Equilibira and Redox Flashcards
(37 cards)
What’s the equation for finding the rate of reaction?
rate of reaction = amount of reactant used or product formed / time
What is reaction rate?
The change in concentration of a reactant or product over time
Name the two conditions that must be maintained for a reaction to happen when particles collide.
1) they collide in the right direction
2) they collide with at least a certain minimum amount of kinetic energy
what is activation energy?
the minimum amount of kinetic energy that particles need to react
How do you give particles extra energy?
You heat them
Do molecules in a gas have all the same amount of energy?
No
What does the peak of the curve on a Maxwell-Boltzmann distribution curve represent?
The most likely energy of any single molecule
Where is the average energy represented on a Maxwell-Boltzmann distribution curve?
Just to the right of the peak of the curve
Why does a Maxwell-Boltzmann distribution curve start a (0,0)?
No molecules have 0 energy
What does the area under a Maxwell-Boltzmann distribution curve represent?
the total number of molecules
Increasing the temperature does what to a reaction? Why?
Makes it faster because the particles will on average have more kinetic energy so moe molecules will have at least the activation energy
What does increasing the temperature do to a Maxwell-Boltzmann distribution curve?
Shifts it to the right
Quite small increases in temperature can lead to what?
To quite large increases in reaction rate
What happens if you increase the concentration? Why?
The rate of reaction increases because the particles will on average be closer together and if they are closer they’ll collide more often
What does increasing pressure do? Why?
Increases rate of reaction. raising the pressure pushes all of the gas particles closer together making them more likely to collide so collisions take place more frequency
What does using a catalyst do?
Make chemical reactions happen faster.
What is a catalyst?
A substance that increases the rate of reaction by providing an alternative reaction pathway with a lower activation energy. The catalyst is chemically unchanged at the end of a reaction
What is dynamic equilibrium?
When the forward reaction will be going at exactly the same rate as the backward reaction so the amounts of reactants and products won’t are changing anymore, it will seem like nothing is happening.
When can dynamic equilibrium happen?
In a closed system
What is Le Chatelier’s principle?
If a reaction at equilibrium is subjected to a change in concentration, pressure or temperature, the position of equilibrium will move to counteract the change
What are homogeneous equilibria?
reactions where every species is in the same physical state
If you increase the concentration of a reactant what does the equilibrium do?
shifts to the right, it tries to get rid of the extra reactant and it does this by making more product
If you increase the concentration of the product what does equilibrium do?
shifts to the left, it tries to remove the extra product
if you increase pressure what does equilibrium do?
the equilibrium shifts to the side with fewer gas molecules and this reduces pressure
