Kinetics Flashcards
What is the collision theory
The collision theory states that for a reaction to occur particles must
Collide
Collide with sufficient energy
Collide with the correct orientation
Define activation energy
The minimum energy required for a successful collision (or for a reaction to occur)
How do you measure rate of reaction
Gradient of a graph
What is the rate of reaction
What is the units for it
The change in concentration per unit time
Mol / dm^3 / s
What 5 factors affect rate of reaction
Concentration
Pressure of gaseous reactants
Surface area of solid reactants
Temperature
Adding a catalyst
How does increasing concentration affect rate of reactants and why (2)
Increase the frequency of collisions because there are more particles moving in the same volume therefore the rate of reaction increases
The proportion of successfull collisions doesnt change because the speed of the particles does not change (temp)
How does increasing the pressure of gaseous reactants affect the rate of reaction
The frequency of collisions increases because there are the same number of particles in a smaller volume so come jn contact more often therefore there are more successful collisions
Proposition of successful collisions doesn’t change
How does increasing the surface area of solid reactants affect the rate of reaction
Increases frequency of collisions because a greater surface is exposed for collisions so there are more successful collisions so a faster rate is reaction
Proportion of successful collisions doesn’t change
How does increasing the temperature affect the rate of reaction
The particles move faster as they have more energy so the frequency of collisions increase
The particles are moving faster so the proportion of successful collisions also increase
What is a maxwell Boltzmann distribution curve
Curve that shows energy against the number of particles in the sample with that energy
How do you draw a MB curve for high and low temperatures? (5)
Number of particle on y axis energy onx axis
The curves cross once
The most probable energy of the curve at higher temp is lower and to the right of low temp curve
The area under the curve to right of activation energy a bigger for high temp
Area under the curve is the same
Why does a small rise in Tempe retainer lead to a large increase in rate of reaction
More collisions
Higher proportion of successful collisions
Many particles have energy greater than activation energy
Describe the MB curve for high and low concentration (5)
No of particles on y axis energy on x axis
The curves don’t cross
Most probable energy for both curves is the same
Area under the curve to the right od activation energy is greater for higher concentration
Area under the curve is greater ata higher concentration
Define a catalyst
Substances that increase the rate of reaction without being used up during the reaction
How do catalysts work
They lower the activation energy by providing an alternative reaction pathway
Increases the proportion of success collisions
