CHEM1112 Lecture Notes - Lecture 27: Reaction Rate Constant, Rate Equation, Reaction Rate
19 May 2018
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Determine the rate law from experimental data, incl
the rate constant and its units
Rate of consumption of reactants/formation of products
Reaction rate = change in conc (M) of a product or reactant per unit
time (s)
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Rate given by gradient of conc vs time graph
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Note: rate of consump and formation are not necessarily the same
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Ie. -slope of tangent
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Reactant = negative, product = positive
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For aA + bB -> cC + dD
Rate of reaction =
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Expressing RATE OF REACTION for each reactant and product
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Rates determined experimentally
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- rate of a reaction = how fast the conc of the molecules present change
Ch 15
27.1
Friday, 3 November 2017
10:57 PM
27. Kinetics Page 1
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RATE LAW, rate of reaction
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Can only be determined experimentally, not from stoichiometric eqn
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K is the rate constant, independent of conc, increases with T
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X is the order of the rxn with respect to A
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Y " " with respect to B
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Overall order = x + y + z…
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No relationship between a and x, b and y etc.
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Rate = k[O3][C2H4]
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Rate of reaction is proportional to the conc [O3] and [C2H4]
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For rxn C2H4 + O3 -> C2H4O + O2
Work out order
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Example
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Calculate k, making k the subject
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27. Kinetics Page 2
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27. Kinetics Page 3
Document Summary
Determine the rate law from experimental data, incl the rate constant and its units. Rate of a reaction = how fast the conc of the molecules present change. Reaction rate = change in conc (m) of a product or reactant per unit time (s) Rate given by gradient of conc vs time graph. Note: rate of consump and formation are not necessarily the same. Expressing rate of reaction for each reactant and product. For aa + bb -> cc + dd. Can only be determined experimentally, not from stoichiometric eqn. K is the rate constant, independent of conc, increases with t. For rxn c2h4 + o3 -> c2h4o + o2. Rate of reaction is proportional to the conc [o3] and [c2h4] Calculate k, making k the subject: kinetics page 2. Screen clipping taken: 4/11/2017 12:26 am: kinetics page 3. Identify the reaction order from the rate law. X is the order of the rxn with respect to a.
