Which value if any corresponds to a faster reaction select...

Which value (if any) corresponds to a faster reaction? Select the single best answer. Δ H o = 19 kJ/mol or Δ H o = −19 kJ/mol 19 kJ/mol −19 kJ/mol Neither value corresponds to a faster reaction.

Transcript

00:02 Okay, so we need to determine which of these conditions could respond to a faster reaction, if any.

00:09 So the first we've got, what if the activation energy were 40 kilojoules versus if it were 4 kilojoules.

00:28 Now remember, this is reaction speed, right? so that's entirely based on activation energy.

00:38 What we're talking about is we're to draw some sort of reaction coordinate diagram, something like this.

00:47 The activation energy is going to tell us how much energy we need to put in to overcome any of these steps.

00:55 And this is what controls the kinetics of the reaction.

01:02 So this would be ea1.

01:04 This would be ea2.

01:05 And that's directly related to speed.

01:11 So the lower the activation energy, the less energy you have to pump in to overcome the energy required to enter the transition state.

01:24 So for that reason, the 4 kilojoule per mole activation energy reaction would be faster than the 40 kilojoules.

01:31 Next, we have a reaction temperature of 0 degrees c versus 25 degrees c.

01:40 So you can think of temperature as being like how much energy is available to the molecules in your beaker or your reaction class, right? and the more energy you have available or the higher temperature, the easier time you're going to have overcoming things like activation energy, right? that's what temperature will do.

01:59 Give these molecules that are at low energy temporarily enough energy to overcome these energy barriers.

02:07 Okay, so reactions done.

02:10 Higher temperatures are faster.

02:13 And so this 25 degree reaction would be faster.

02:17 Okay, next we have the comparison of a reaction with an equilibrium constant of 10 versus an equilibrium constant of 100.

02:30 Now, what is equilibrium constant about? remember, equilibrium constant is related to delta g, right? delta g equals negative r t l n k natural log of k eq if you will and so this is purely related to the thermodynamics of the reaction that is the difference in energy between the reactants or the starting materials sm and the products p so both delta g and the equilibrium constant and care only about the difference in energy between the reactants and the products...

Question

Which value (if any) corresponds to a faster reaction? Select the single best answer. Δ H o = 19 kJ/mol or Δ H o = −19 kJ/mol 19 kJ/mol −19 kJ/mol Neither value corresponds to a faster reaction.

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