Term
| What is the rate of reaction? |
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Definition
| The change in concentration of a reactant per unit time. Therefore its units are moldm-3s-1.It is a measure of the rate of use of reactants and the rate of production of products. |
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Term
What is the rate equation? Use [A] and [B] as the reactatnts and m and n as the orders of reactions. |
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Definition
rate of reaction=k[A]m[B]n |
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Term
Why can't the rate equation be predicted from the stoichiometric equation? How is it calculated? |
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Definition
| The stoichiometric equation cannot be used to find the rate equation because the units for k may be different for each reaction. The rate equation must be worked out by experimentation. |
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Term
| How is the overall order of reaction calculated? |
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Definition
The overall order of reaction is the sum of the individual orders of the reactants. |
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Term
The order of reaction may be determined by which method? Describe this method. |
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Definition
| The order of reaction may be determined by the initial-rates method. The initial rate is measured for several experiments, using different concentrations of reactants. One concentration is changed whilst the others are fixed, so that a clear and systematic set of results is obtained. |
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Term
| The order of reaction may be determined from a single experiment. Explain how this is done. |
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Definition
| Draw a concentration-time graph for this experiment. The shape of the graph, indicates the order of reaction (see fig12.7 pg 109 of Chemistry 2 for shapes). The gradient of a tangent drawn at a point is the rate of reaction at that point. |
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