Topic 9 Kinetics 1 Flashcards
What is chemical kinetics?
The study of the rate of chemical reactions.
What is the rate of reaction?
The rate of which a product is formed or reactant is removed.
This can be measured by analysing a property of the mixture such as the volume, and observing how it changes over time.
What is a catalyst?
A substance that increases the rate of reaction without altering the reaction that occurs.
Catalysts work by removing or lowering barriers preventing a reaction.
What is the mechanism of a reaction?
A description of how a reaction occurs displaying the bonds which are broken and made.
What is a phase?
A phase is one of the three states of matter. Solid, liquid or gas.
What is a heterogenous catalyst?
A catalyst that is in a different phase from the reactants in the reaction.
What is the Maxwell-Boltzmann Distribution?
A graph that displays the spread of molecular kinetic energies for a gas at a particular temperature.
It displays that there is a wide spread of molecular energies so the molecules are moving at different speeds.
What is activation energy?
The minimum energy required for successful collisions between molecules to occur.
What is a transition state?
The state of the reacting atoms, molecules or ions when they reach the required activation energy in a reaction.
Transition states occur for such a short period of time that they can not be detected or isolated.
What is a reaction profile?
A graph which shows the total enthalpy of the atoms, molecules or ions changes during the progress of a reaction from reactants to products.
What are intermediates?
Atoms, molecules and ions which do not appear in the balanced equation but which are formed during one step of a reaction, and then used up in the next step.
How does temperature affect the rate of reaction?
Increased temp - Particles gain more kinetic energy, therefore resulting in more frequent successful collisions, resulting in a faster rate of reaction.
Decreased temp - Particles gain less kinetic energy, therefore resulting in less frequent successful collisions, resulting in a slower rate of reaction.
How does pressure affect the rate of reaction?
Increased pressure - Particles are closer together, therefore resulting in more frequent successful collisions, resulting in a faster rate of reaction.
Decreased pressure - Particles are further apart, therefore resulting in less frequent successful collisions, resulting in a slower rate of reaction.
How does surface area affect the rate of reaction?
Increased SA - A higher number of particles are able to react, therefore resulting in more frequent successful collisions, resulting a faster rate of reaction.
Decreased SA - A lower number of particles are able to react, therefore resulting in less frequent successful collisions, resulting a slower rate of reaction.
How does a catalyst affect the rate of reaction?
With catalyst - The activation energy is lowered, so more particles have the required activation energy, therefore resulting in more frequent successful collisions, resulting in a faster rate of reaction.
Without catalyst - No change
