Rate of Reaction Flashcards
What is Collision theory?
Chemical reactions can occur only when reacting
particles collide with each other and with sufficient energy.
What is Activation energy?
The minimum amount of energy that particles must collide with to react.
What is a Catalyst?
Catalysts increase the rate of reaction by providing a different pathway for the reaction that has a lower activation energy. They are not used up during the reaction.
What is the Effect of concentration on reaction rate?
Increasing the concentration of reactants in
solution means the reacting particles will be closer together. This means they will collide more often so there will be a higher rate of successful collisions and a faster rate of reaction
What is the Effect of pressure on reaction rate?
Increasing the pressure of gaseous reactants means
the reacting particles will be closer together. This means they will collide more often so there will be a higher rate of successful collisions and a faster rate of reaction.
What is the Effect of surface area on reaction rate?
Increasing the surface area of the reactants means
there are more exposed reacting particles. This means there are more frequent successful collisions so the rate of reaction increases.
What is the Effect of temperature on reaction rate?
Increasing the temperature means the particles will have more kinetic energy and so will move faster.
If the molecules are moving faster they will collide more often and, since they’ve gained kinetic energy, a larger proportion of the particles will have at least the activation energy.
For both these reasons the rate of reaction increases.
What is Rate of reaction?
The measure of the amount of product formed or reactant used over time.
What is a Reversible reaction?
Reactions in which the products from the reaction can react together to
form the original reactants.
The direction of reversible reactions can be changed by changing the conditions.
What is Equilibrium?
When a reversible reaction occurs in apparatus which prevents the escape of reactants and products, equilibrium is reached when the forward and reverse reactions occur at exactly the same rate.
What is Le Chatelier’s Principle?
If a reaction at equilibrium is subjected to a change in concentration, temperature or pressure, the position of equilibrium will move to
counteract the change.
What is the Effect of changing concentration on equilibrium?
If the concentration of a reactant is
increased, more products will be formed until equilibrium is reached again. If the
concentration of a product is decreased, more reactants will react until equilibrium is
reached again.
What is the Effect of changing pressure on equilibrium
An increase in pressure causes the
equilibrium position to shift towards the side with the smaller number of molecules. A
decrease in pressure causes the equilibrium position to shift towards the side with the
larger number of molecules.
What is the Effect of changing temperature on equilibrium?
If the temperature of an equilibrium
system is increased then the relative amount of products at equilibrium increases for
an endothermic reaction and decreases for an exothermic reaction
Name three common ways of
measuring rate of reaction
- Loss in mass of reactants
- Volume of gas produced
- Time for a solution to become opaque
