Rates and Equilibrium Flashcards
Activation Energy
Minimum amount of energy required for a reaction to take place.
Rate of reaction
The change in concentration of a reactant or product per unit time
Temperature
A measure of kinetic energy of the particles of a substance
Catalyst
A substance which speeds up the rate of reaction by lowering the activation energy, remaining unchanged by the reaction
Average Rate of Reaction
The change in concentration of a reactant or product per unit time, as measured over a certain time period.
Formulae to calculate average rate of reaction
(change in quantity) / (change in time)
Maxwell-Boltzmann Distribution
A graph showing the distribution of energy across a sample of particles
Reversible Reaction
A chemical reaction that can occur in either the forward or reverse direction, given appropriate conditions
Closed System
A system in which no substances can escape or be added
Dynamic Equilibrium
A situation in which the rate of the forward and reverse reactions are equal, resulting in no observable change over time.
Yield
The amount of product produced
Position of equilibrium
An evaluation of the relative amount of products compared to reactants.
At equilibrium, if more products are present, equilibrium is said to be on the…
Right
At equilibrium, if more reactants are present, equilibrium is said to be on the…
Left
Le Chatelier’s Principle
A system at equilibrium has a tendency to partially oppose a disruption
What is collision theory
In order for a reaction to occur, particles must collide with the correct orientation and sufficient energy to disrupt the bonds in their molecules.
How can the rate of a reaction be altered?
- change the surface area of a solid reactant
- change the temperature
- change the concentration of a solution
- change pressure of gases
- using a catalyst
Explain how increasing the surface area of a solid increases rate of reaction
Increasing surface area, increases the frequency of successful collisions between reactant particles per unit time
Explain how increasing the concentration of a reactant increases rate of reaction
Increasing concentration increases the frequency of successful collisions between reactant particles per unit time
Explain how decreasing volume, to increase pressure, increases the rate of a reaction between gas molecules.
Increasing pressure of a gaseous system increases the frequency of successful collisions between reactant particles per unit time
Explain how increasing temperature increases the rate of reaction
Increasing temperature increases the kinetic energy of the particles, increasing the proportion of particles with energy equal to or greater than the activation energy therefore increasing the number of successful collisions between reactant particles per unit time.
Which reaction occurs fastest? 0, 1000 or 2000 degrees Celsius
The reaction at 2000oC.
Because the reaction at 2000oC has more kinetic energy than the reactions at 1000oC or 0oC ,at 2000oC there is a greater number of particles with energy greater than or equal to the activation energy (EA) compared to 1000oC or 0oC.
Therefore, there are more successful collisions between the reactant molecules per unit time.
Explain how a catalyst increases the rate of reaction
Catalysts lower the activation energy of a reaction by providing an alternative pathway for the reaction to occur. This increases the proportion of particles with energy equal to or greater than the activation energy which results in a greater frequency of successful collisions per unit time
