kineticsyear 2 Flashcards
what is rate of reaction
it is defined as the change in concentration of a substance in unit time
what happens when you plot a graph with concentration against time
when a graph concentration of reactants is plotted vs time we can form a gradient which is equal to the rate of reaction
what is the initial rate
the initial rate = rate at the start of the reaction whee it is fastest
what are some techniques used to investigate the rate of reaction
- measurements of the change in volume gas
- measurement of change of mass
- titrating a samples of reaction mixture with acid, alkali and sodium thiosulphate
- colorimetry
- measuring change in electrical conductivity
- measurement of optical activity
what are rate equations
rate equation relates mathematically
the rate if reaction to concentration of the reactants
what is the total order
the total amount of all the individual orders
what is the units for rate
mol dm-3 s-1
what does first order mean
1st order = rate of reaction is directly proportional to the product (A)
what is the 2nd order
2nd order= rate of reaction is directly proportional to the concentration of the product squared
what is the units of the orders
1st order units of k = s-1
2nd order overall reaction units of k = mol-1dm3 s-1
3rd order = mol-2dm6 s-1
what are catalysts in terms of
catalysts can’t be order of 0 because the whole point of a catalyst is that it increases the rate of reaction
you can work out what is a catalyst in a reaction as it appears in the rate equation but not the overall equation
what is the only condition that would change the value of k
temperature and surface area
what are intermediates
they are products that are made in one step in a reaction mechanism and then used up in another step
