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19 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is the Arrhenius equation |
Linking activation energy and temperature to the rate constant Can be used to calculate activation energy or rate constant |
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What does gradient of vol-time graph show |
Rate of reaction |
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What is a clock reaction and it’s assumptions |
Reaction to time how long it takes for a reaction to occur - temperature of reaction is constant - conc of reactants doesn’t change significantly - reaction doesn’t go beyond end point Rate of clock reaction is assumed to be equal to initial reaction |
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Iodine clock experiment |
Add sodium thiosulfate and starch to excess H2O2 Sodium thiosulfate reacts with iodine produced in the reaction When sodium thiosulfate runs out, iodine reacts with starch to give black colour |
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Rate equation |
A and B only reactants |
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What is zero order |
Changes in concentration has no effect on rate - if [A] doubles, rate doesn’t change |
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What is order of reaction |
Power to which a concentration is raised to in the rate equation Tells us how concentration of substance affects the rate Can only be determined by practical experiments |
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What is second order |
Changes in concentration has a squared proportional change on rate If [A] doubles, rate quadruples |
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What is rate constant k |
Number that allows us to equate rate and concentration Increasing temp, increases k due to more kinetic energy Larger k means faster rate of reaction, but concentration of substances constant |
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What does rate-concentration graph show |
Help to identify the order Create these graphs with known values of rates |
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What does Concentration time graph |
Work out rate using the gradient Results from practical used to plot the graph |
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Rate graphs for first second and third order shapes |
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Conc goes down Rate goes up |
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What is half life and what does it show |
Time it takes half of the reactant to be used up Can be used to calculate rate constant Half life represented by t1/2 Units: s-1 |
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Half life of first order |
Each half life same length K= ln2/t1/2 |
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Initial rate method to investigate rate of reaction |
- repeat experiment several times, but changing the concentration of each reactant - work out initial rate of reaction by plotting graph conc time graph and working out gradient at 0 - record rate and conc to plot a graph - work out order - work out rate using equation |
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What is rate determining step |
The slowest step in a multi step reaction Determines rate of whole step |
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How to increase rate of reaction |
Use a catalyst or change temp to speed |
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Working out rate equation with multi step reactions |
Back (Definition) |
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What is the Arrhenius equation |
Linking activation energy and temperature to the rate constant Can be used to calculate activation energy or rate constant |
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