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7 Cards in this Set
- Front
- Back
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Define 'rate of reaction'.
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A change in concentration of a reagent or product measured against time.
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How would you tell if a reaction was zeroth, first or second order.
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If when you double the concentration of a compound the rate stays the same it is zeroth order with respect to that compound, if when you double the concentration the rate also doubles it is 1st order with respect to that compound, if the rate quadruples it is second order.
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Write a general expression for the rate equation.
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Rate=k[A]m[B]n
(m and n stand for the order with respect to that reagent so if 0th order it would be 0 if 1st 1 and if 2nd 2. |
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What is the rate determining step of a reaction?
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The slowest step of the mechanism.
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How would you confirm that a mechanism is compatible with the rate equation.
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It must have the same number of moles of a compound in the slow step as are in the rate equation. E.g Rate=k[N2O5]1 means that there must only be one mole of N2O5 in the slow step. Also there needs to be the same number of moles of products and reagents in all the steps as there are in the overall equation.
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What will increasing the temperature do to the rate of the equilibrium reaction 3H2 + N2 <-> 2NH3?
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The rate of reaction will increase (watch out, the question asks about the rate not the direction of the reaction) This is because the no. of particles that possess the activation energy has increased so there are more successful collisions.
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Give the different ways that you could measure the rate of a reaction.
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1)Measure a change in pH over time perhaps with an indicator or digital pH meter.
2)Using a gas syringe to measure a volume of gas produced. 3)Measure a change in colour over time using a colorimeter. |
