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# Kinetics

Chemistry discussion, revision, exam and homework help.

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1. Kinetics

Is my drawn graph correct? I know that if the temperature is lower, the graph has to have a higher peak and the peak has to be to the left, but I am not sure about the lower part of the graph? Also, if the drawn graph touched the x-axis would it be wrong?
2. Re: Kinetics
Yes , your graph is correct and you are right it shouldn't touch the x-axis.
3. Re: Kinetics
Yes , your graph is correct and you are right it shouldn't touch the x-axis.
Thanks, do you know why the graph T2 (in the below image) finishes above the graph T1? (instead of following the red path)

I thought a graph (that represents higher temperature) always finishes below the graph that represents a lower temperature..

4. Re: Kinetics
T1 begins above but finishes below T2 cos the area under each curve has the be the same (meaning the total number of molecules doesn't change)
5. Re: Kinetics
(Original post by sabre2th1)
Thanks, do you know why the graph T2 (in the below image) finishes above the graph T1? (instead of following the red path)

I thought a graph (that represents higher temperature) always finishes below the graph that represents a lower temperature..

At higher temperatures, the peak is lower, to the right, and its EA is higher than a lower temperature.

Its EA is higher, as more molecules have enough EA at the higher temperature than at the lower temperature.
6. Re: Kinetics
(Original post by sabre2th1)
I thought a graph (that represents higher temperature) always finishes below the graph that represents a lower temperature..

This is incorrect, the line representing a higher temperature will finish above the line representing the lower temperature, because more particles have a higher kinetic energy.
7. Re: Kinetics
(Original post by thegodofgod)
At higher temperatures, the peak is lower, to the right, and its EA is higher than a lower temperature.

Its EA is higher, as more molecules have enough EA at the higher temperature than at the lower temperature.
What do you mean with higher Ea? Doesn't the line remain in the same position?
8. Re: Kinetics
(Original post by sabre2th1)
What do you mean with higher Ea? Doesn't the line remain in the same position?
EA is activation energy, which is the energy required for particles to break their existing bonds to form new bonds.

yes the activation energy does remain the same, but increasing the temperature increased the molecular energies, which means that there are more molecules with higher energy then the activation energy, hence the graph's peak is lowered and is shifted towards the right. So this is why the rate of reaction increases.
9. Re: Kinetics
(Original post by sabre2th1)
What do you mean with higher Ea? Doesn't the line remain in the same position?

I meant to say that at a higher temperature, more particles will have energy equal to or greater than EA, so they can react. This means that as you increase temperature, the rate of reaction increases.
10. Re: Kinetics
the lower the temp the lower the line will be at the finnish
11. Re: Kinetics
(Original post by cuckoo99)
the lower the temp the lower the line will be at the finnish

(Original post by thegodofgod)

I meant to say that at a higher temperature, more particles will have energy equal to or greater than EA, so they can react. This means that as you increase temperature, the rate of reaction increases.

(Original post by UserInvalid)
EA is activation energy, which is the energy required for particles to break their existing bonds to form new bonds.

yes the activation energy does remain the same, but increasing the temperature increased the molecular energies, which means that there are more molecules with higher energy then the activation energy, hence the graph's peak is lowered and is shifted towards the right. So this is why the rate of reaction increases.

(Original post by Nick_)
This is incorrect, the line representing a higher temperature will finish above the line representing the lower temperature, because more particles have a higher kinetic energy.
I understand now, thank you all
12. Re: Kinetics
Yes , your graph is correct and you are right it shouldn't touch the x-axis.
why shouldn't it touch the x axis?
the area underneath the graph is finite, it represents the total number of molecules in the system. it will eventually touch the x axis.

Edit: my mistake, i understand now, no molecules within the system will have 0 energy.
Last edited by s.aley; 20-05-2012 at 14:52. Reason: mistake
13. Re: Kinetics
(Original post by s.aley)
why shouldn't it touch the x axis?
the area underneath the graph is finite, it represents the total number of molecules in the system. it will eventually touch the x axis.

Edit: my mistake, i understand now, no molecules within the system will have 0 energy.
There graph does touch the x-axis at the origin because no particles have 0 energy, however it does not touch the x-axis again because there is no limit to the amount of energy particles could have (within reason).

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Last updated: May 20, 2012
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