C6: rates of reaction Flashcards
(11 cards)
State the equations to find the mean rate of reaction
quantity of product formed / time taken
OR
quantity of reactant used / time taken
Describe the effect of changing the concentration / pressure of a reaction
If the concentration, pressure increases so will the rate of reaction. They are proportional.
Explain the effect of changing the concentration / pressure of a reaction
Because there are more molecules, there will be more successful collisions leading to a higher rate of reaction
What is collision theory?
Chemical reactions can only take place when the reacting particles collide with each other. The collisions must have sufficient energy. The rate of a chemical reaction is determined by the frequency of successful collisions
Describe the effect of surface area of solid reactants on the rate of reaction.
Because only the particles on the surface can react. The larger the surface area, the faster the reaction because we have more successful collisions. Greater surface area to volume ratio.
Describe the effect of temperature on the rate of a chemical reaction
As you increase the temperature, the rate of chemical reaction increase. They have more energy, so this increases the frequency of collisions as well as the likelihood that they will overcome the activation energy barrier.
What is the activation energy?
The minimum amount of energy that the particles must have in order to react.
What effect do catalysts have on the rate of reaction?
They increase the rate of reaction. They provide a different energy pathway for the reaction that has a lower activation energy.
What is a catalyst?
Something that increases the rate of ration but is not used up during the reaction
What is a reversible reaction?
The products can react to reform the original reactants
What is equilibrium?
The forward and reverse reactions take place at the same rate so there is no overall change.
