Define thermodynamic stability and kinetic inertness. Watch

Fatima SJ
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#1
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Could someone please describe thermodynamic stability and kinetic inertness in simple words according to A level chemistry as its mentioned in the specification.
Please clearly mention the difference between the two.
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hayden0101
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Thermodynamic Stability- All down to Ssystem and Ssurroundings (Total Entropy change)- the entropy changes mean that the reaction can occur spontaneously
Positive Entropy change = Reactants are said to be thermodynamically unstable relative to products
Negative entropy change= Reactants are said to be thermodynamically stable relative to products, the entropy of system and surroundings mean that the reaction will not occur spontaneously/ will be feasible.

Kinetic Stability emphasises that whilst a reaction might be thermodynamically feasible, the activation energy barrier for the molecules to react might be too high for the reaction to proceed.
So you might have to add large amounts of heat ( for example a decomposition reaction you may calculate that the Total Entropy change favours the reaction at say 298K, but in reality, you know for a fact that decomp reaction involvess large amount of heat etc)

If applying the same thing mentioned before with thermodynamic stability
High EA = Reactants = kinetically stable relative to products
Low Ea = Reactants = kinetically unstable relative to products

It helps to visualise when say 'relative' like you would when you draw an enthalpy diagram
Hope it helps man sorry for the long winded para
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Fatima SJ
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(Original post by hayden0101)
Thermodynamic Stability- All down to Ssystem and Ssurroundings (Total Entropy change)- the entropy changes mean that the reaction can occur spontaneously
Positive Entropy change = Reactants are said to be thermodynamically unstable relative to products
Negative entropy change= Reactants are said to be thermodynamically stable relative to products, the entropy of system and surroundings mean that the reaction will not occur spontaneously/ will be feasible.

Kinetic Stability emphasises that whilst a reaction might be thermodynamically feasible, the activation energy barrier for the molecules to react might be too high for the reaction to proceed.
So you might have to add large amounts of heat ( for example a decomposition reaction you may calculate that the Total Entropy change favours the reaction at say 298K, but in reality, you know for a fact that decomp reaction involvess large amount of heat etc)

If applying the same thing mentioned before with thermodynamic stability
High EA = Reactants = kinetically stable relative to products
Low Ea = Reactants = kinetically unstable relative to products

It helps to visualise when say 'relative' like you would when you draw an enthalpy diagram
Hope it helps man sorry for the long winded para
So the more energy the reactants have the more unstable they become?
thanks alot
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hayden0101
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don't take the energy (enthalpy) so literally, i only mentioned it as it's a nice way of comparing the reactants to the products using thermodynamic stability.
Just apply the 4 points i gave you i an exam and you'll be fine
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