Reaction Rates Flashcards
What is the equation used to calculate rate
Rate = change in concentration / time
What is the unit for rate of reaction
mol dm-3 s-1
What must particles dop in order to react
Collide with sufficient energy and the correct orientation
What are the factors that affect rate of reaction
Temperature
Pressure
Concentration
Surface area
Catalyst
How does temperature affect rate of reaction
Increasing temperature, increases rate of reaction
Much higher proportion of particles have energy greater than the activation energy
Many more successful collisions per second
Increase rate
How does concentration affect rate of reaction
Increased concentration, increases rate of reaction
More particles per unit volume, so more frequent successful collisions
What variables in an experiment can be monitored to calculate the rate
Concentration of reactant or product
Volume of gas produced
Mass of substances formed
How to calculate rate from a concentration time graph
Draw a tangent
Work out the gradient of the tangent
Change in y / change in x
What is a catalyst
A substance which increases the rate of reaction but is not used up in the reaction
How do catalysts increase the rate of reaction
They lower the activation energy need for a reaction to occur by offering an alternative reaction pathway
Means more particles have energy, so more frequent successful collisions
What is a homogeneous catalyst
A catalyst that is in the same phase as the reactants
What is a heterogeneous catalyst
Catalyst used in the reaction is in a different phase as the reactants
Define activation energy
The minimum energy that particles must collide with for a reaction to occur
What are the axis in a Boltzmann distribution curve
X - energy
Y - number of molecules
