# Define thermodynamic stability and kinetic inertness.

Watch
Announcements
#1
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.
0
5 years ago
#2
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
0
#3
(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
0
5 years ago
#4
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
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### Current uni students - are you thinking of dropping out of university?

Yes, I'm seriously considering dropping out (22)
17.74%
I'm not sure (2)
1.61%
No, I'm going to stick it out for now (39)
31.45%
I have already dropped out (3)
2.42%
I'm not a current university student (58)
46.77%