Kinetics Flashcards
Define Activation energy
The minimum amount of energy that particles must collide with in order for a reaction to take place.
What 3 things does a catalyst do
Increases the rate of reaction
May be completely recovered , chemically unchanged at the end of the reaction.
Help by making it easier for particles to react, providing an alternative pathway with a lower activation energy.
How do you work out the concentration
Amount of solute
Concentration = —————————
Volume of solution
Describe two ways in which we can measure how far the reaction between Calcium carbonate and Hydrochloric acid has proceeded.
Constantly measure the mass as CO2 leaves the flask
Measuring the volume of the CO2
Why is there cotton wool on the beaker i the reaction between HCL and CaCO3
To stop acid spray
How do you find the mass of reactant after an experiment
Amount of reactant used up
Rate = ——————————————-
Time
How would you find the volume of product formed over time
Amount of product formed
Rate = —————————————-
Time
What 4 factors affect the rate of reaction
Temperature
Concentration of solution (or pressure of a gas)
Surface area of a solid
Catalysts
What is the collision theory
For any reaction to occur, the particles must COLLIDE with ENOUGH ENERGY to OVERCOME THE ACTIVATION ENERGY.
How does surface area increase the rate of reaction
By increasing the surface area of a solid, it increases the rate because more particles are exposed to the other reactant, so the PARTICLES COLLIDE MORE FREQUENTLY.
How does changing the concentration change the rate of reaction
Increasing the concentration of a solution, increases the rate of reaction because it means that there are more particles per unit volume so the particles cold more frequently
How does the temperature of a reaction mixture affect the rate of reaction
1) If you increase the temperature, particles have more energy.
2) More particles have the minimum activation energy.
3) So more successful collisions per second
4) The rate of reaction increases
In the practical between Acid and Thiosulfate, what are the dangers
Silver dioxide is released which is toxic and can trigger athematic attacks.
How would you set up a practical to see how temperature affects the rate of reaction
Set up a water bath over a bunsen burner
Measure 50cm3 of sodium thiosulfate in a conical flask, place the flask in the water bath and put a thermometer in.
When the thiosulphhate has reached the desired temperature, place the flask on the cross.
Add the acid at the same time as starting the timer, time how long it take s for the cross to disappear.
Do this with a range of different temperatures up to 55˚C
How does adding catalyst change the rate of reaction
Adding a catalyst, increases the rate reaction, because it provides an alternative pathway with a lower activation energy. This means more particles have enough energy to overcome the minimum activation energy.
