2.2 - Rates of reaction Flashcards
Define rate of reaction
The change in concentration of a reactant or product per unit time
How do you calculate rates from a graph?
Chnage in y / change in x
equation of rate
1/time
Define collision theory
For a reaction to take place the molecules must collide with enough energy in the correct orientation.
5 Factors effecting rate
conc
temp
size of particle
catalyst
light
Activation energy
Minimum amount of energy required for a reaction to occur by breaking bonds.
How do you show Ea on a graph
distance between the reactants to the top of the curve
How do you find enthalpy change?
difference between products and reactants.
How do you show an increase in temp on Boltzmann distribution curve?
shift to the left and higher ea reigion
Define catalyst
A substance that increases the rate of reaction without changing the conc of products made. It provides an alternative route for the reactants to take with a lower activation energy.
Homogeneous catalyst
The catalyst is in the same physical state as the reactants .
Heterogenous catalyst
The catalysts in a different physical state to the reactants.
Industrial advantages of catalysts
-increase rate so high temps are not needed
-less fossil fuels
-lower pressure so less robust equipment would be needed.
3 variables that can bemeasured to measure rate
-gas volume (gas syringe)
-gas pressure (manometer)
-mass (weighing scales)
Describe calorimetry
-measures the concentration of the substance that changes colour
-selects lazer that will be absorbed by the sample
-light passes through and onto detector/photocell
-electrical signal developed
-colorimeter is calibrated.
