- #1
adf89812
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- TL;DR Summary
- When to Multiply by Constants and do exponentiation in rate law equation ?
When to use exponents or multiply by constants in the rate law?
In summary, the decision to use exponents or multiply by constants in the rate law depends on the nature of the reaction and the relationship between reactant concentrations and reaction rate. Exponents indicate the order of the reaction with respect to each reactant, reflecting how changes in concentration affect the rate. In contrast, multiplying by constants is appropriate when the relationship is linear or when the reaction rate is proportional to the concentration without exponentiation. Understanding the underlying reaction mechanism and experimental data is crucial for determining the correct form of the rate law.
- #2
Borek
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You raise concentration to the power given by the stoichiometric coefficient, internal structure of the molecule (amount of atoms of different elements) doesn't matter (well, it can matter for the mechanism, but for a single step kinetics these are just black boxes doing some magic).
This is not different from the way reaction quotient is defined.
This is not different from the way reaction quotient is defined.
- #3
adf89812
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where does the doubling in theBorek said:
- #4
Borek
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Rate of the reaction is ##k_3[H_2][ I]^2## but because of the stoichiometry I is consumed twice as fast.
- #5
adf89812
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The stoichiometry coefficient of two means both double the speed and square the exponent on the concentration term always?Borek said:
- #6
adf89812
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the stoichiometry coefficient on the reactant side of the decomposition has two effects always?adf89812 said:
- #7
Borek
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Many ways to skin that cat. In general it is perfectly possible to do the calculations without doubling the rate, but this stoichiometry coefficient needs to be used at some point.
- #8
adf89812
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If there were homonuclear triatomic molecules, would that mean cubed the corresponding concentration but don't multiple the rate by three unless the stoichiometry means it's concentration is three times that of the others?Borek said:
- #9
Borek
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adf89812 said:
Why? I already told you whatever is inside the molecule doesn't matter.