RATE AND EXTENT OF REACTIONS DEFINITIONS Flashcards
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 does collision theory state?
According to this theory, chemical reactions can occur only when reacting particles collide with each other and with sufficient energy.
How does changing concentration affect 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.
How does changing pressure affect 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.
How does changing temperature affect 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.
How does concentration affect reaction rate?
Increasing the concentration of reactants in solution means the reacting particles will be closer together, leading to more frequent successful collisions and a faster rate of reaction.
How does pressure affect reaction rate?
Increasing the pressure of gaseous reactants means the reacting particles will be closer together, resulting in more frequent successful collisions and a faster rate of reaction.
How does surface area affect reaction rate?
Increasing the surface area of the reactants means there are more exposed reacting particles, leading to more frequent successful collisions and an increased rate of reaction.
How does temperature affect reaction rate?
Increasing the temperature means the particles will have more kinetic energy and move faster, resulting in more frequent collisions and a larger proportion of particles having at least the activation energy, thus increasing the rate of reaction.
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 rate of reaction?
The measure of the amount of product formed or reactant used over time. The units of rate of reaction may be given as g/s, cm3/s or mol/s.
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.
