4.30

[Hannah Holden 3F]

Can someone explain why the reaction in problem 4.30 will not occur at room temperature? I'm assuming this is because delta G is negative. But how do you find this with the information given?

[Chem_Mod]

Can you post the problem statement please? IT may be related to G=H-TS

[Ryan McDonough 4E]

The question asks:
"The activation energy, Ea, in organic reaction is known to be 125kJ.mol^(-1). Will this reaction occur at room temperature?

Do we use the G=H-TS equation, and if so, where do we find S, H, and G?

[Chloe 3D]

I'm not sure about using that equation, but I found a general rule from the Chapter 4 reading. It said only reactions with activation energies at or below roughly 80 kJ.mol-1 will occur at room temperature.

[Ilana Golub 1A]

Hi there!

I took this to be a rather intuitive question rather than one that is calculation based. The problem tells us that we have an activation energy of 125kJ/mol. Comparing this value to the others given thus far in our experience with activation energy....woah...this one is pretty huge! We know that a reaction with a larger activation energy has a higher energy barrier; hence, much more energy must be supplied for the reaction to occur. The higher the temperature, the more energy supplied!

Because this activation energy is so large, we can conclude that this reaction simply does not spontaneously take place at room temperature--a relatively low temperature.

Hope this helps!