Rate of reaction affected by increasing temperature

[98.40_for_sure]

Can anyone tell me if this is correct, or if im missing something.

This is copy and pasted from an answer to my 'rate of reactions' prac report

An increase in temperature affects the rate of a reaction as the particles have increased speed and kinetic energy. The increase in kinetic energy means the particles move faster, thus more frequent collisions. However, we need to consider the collision theory that states ‘particles must collide with sufficient energy to overcome the activation energy barrier’. So the increase in temperature causes higher kinetic energies, but only the particles colliding with more energy than the activation energy of the reaction causes the rate of the reaction to increase. The proportion of particles with more energy than the activation energy increases. If we consider a graph of kinetic energy vs number of particles, we see that an increase in temperature causes the curve to shift to the right, causing a larger area under the curve that is beyond the EA. This means there are more particles that are beyond the activation energy, so there will be more fruitful and frequent collisions, resulting in the faster rate of reaction.

[tram]

it looks right to me....

Basically, increasing tempreture does two things

1) Increases the total amount of collision happening per second. This is becuase the particles are moving at a higher speed.

2) Increases the Kinetic energy of the particles. This means that more of the collisons that occur are fruitful.

We know the rate of fruitful collisions= rate of collisions x proportion of fruitful collisions

Thus the effect of incresing the tempreture of recation is two fold as it increases both of the factors that determine the rate of fruitful collisions.

[98.40_for_sure]

it looks right to me....

Basically, increasing tempreture does two things

1) Increases the total amount of collision happening per second. This is becuase the particles are moving at a higher speed.

2) Increases the Kinetic energy of the particles. This means that more of the collisons that occur are fruitful.

We know the rate of fruitful collisions= rate of collisions x proportion of fruitful collisions

Thus the effect of incresing the tempreture of recation is two fold as it increases both of the factors that determine the rate of fruitful collisions.

Ooh thanks man

I hope you don't mind if i use some of that to add to my paragraph

I just chucked what you wrote on the end pretty much to sum it up

An increase in temperature affects the rate of a reaction as the particles have increased speed and kinetic energy. The increase in kinetic energy means the particles move faster, thus more frequent collisions. However, we need to consider the collision theory that states ‘particles must collide with sufficient energy to overcome the activation energy barrier’. So the increase in temperature causes higher kinetic energies, but only the particles colliding with more energy than the activation energy of the reaction causes the rate of the reaction to increase. The proportion of particles with more energy than the activation energy increases. If we consider a graph of kinetic energy vs number of particles, we see that an increase in temperature causes the curve to shift to the right, causing a larger area under the curve that is beyond the EA. This means there are more particles that are beyond the activation energy, so there will be more fruitful and frequent collisions, resulting in the faster rate of reaction. So effectively, increasing the temperature does two things; it increases the total amount of collisions happening per second due to the particles moving at a higher speed, and increases the kinetic energy of the particles resulting in more fruitful collisions. The rate of fruitful collisions depends on the rate of collisions and the proportion of fruitful collisions. Thus the effect of increasing the temperature is twofold as it increases both of the factors that determine the rate of fruitful collisions.

[Martoman]

Full marks from me.  :angel:

[tram]

it looks right to me....

Basically, increasing tempreture does two things

1) Increases the total amount of collision happening per second. This is becuase the particles are moving at a higher speed.

2) Increases the Kinetic energy of the particles. This means that more of the collisons that occur are fruitful.

We know the rate of fruitful collisions= rate of collisions x proportion of fruitful collisions

Thus the effect of incresing the tempreture of recation is two fold as it increases both of the factors that determine the rate of fruitful collisions.

Ooh thanks man

I hope you don't mind if i use some of that to add to my paragraph

I just chucked what you wrote on the end pretty much to sum it up

An increase in temperature affects the rate of a reaction as the particles have increased speed and kinetic energy. The increase in kinetic energy means the particles move faster, thus more frequent collisions. However, we need to consider the collision theory that states ‘particles must collide with sufficient energy to overcome the activation energy barrier’. So the increase in temperature causes higher kinetic energies, but only the particles colliding with more energy than the activation energy of the reaction causes the rate of the reaction to increase. The proportion of particles with more energy than the activation energy increases. If we consider a graph of kinetic energy vs number of particles, we see that an increase in temperature causes the curve to shift to the right, causing a larger area under the curve that is beyond the EA. This means there are more particles that are beyond the activation energy, so there will be more fruitful and frequent collisions, resulting in the faster rate of reaction. So effectively, increasing the temperature does two things; it increases the total amount of collisions happening per second due to the particles moving at a higher speed, and increases the kinetic energy of the particles resulting in more fruitful collisions. The rate of fruitful collisions depends on the rate of collisions and the proportion of fruitful collisions. Thus the effect of increasing the temperature is twofold as it increases both of the factors that determine the rate of fruitful collisions.

HEY THAT WAS COPYRIGHTED TOTALLY GONNA HUNT YOU DONW AND SUE YOU jks, nah, happy to help

and yea, papragraph=awesome

[98.40_for_sure]

Full marks from me.  :angel:

Do a DipEd and become a teacher

[linahh123]

Quote:
"So the increase in temperature causes higher kinetic energies, but only the particles colliding with more energy than the activation energy of the reaction causes the rate of the reaction to increase."

Correct me if i'm wrong, but isn't it the particles with energy "equal to or greater than the activation energy"?

[98.40_for_sure]

Quote:
"So the increase in temperature causes higher kinetic energies, but only the particles colliding with more energy than the activation energy of the reaction causes the rate of the reaction to increase."

Correct me if i'm wrong, but isn't it the particles with energy "equal to or greater than the activation energy"?

I think you're correct, but does i don't know if it matters... for a perfectionist certainly

[akira88]

Quote:
"So the increase in temperature causes higher kinetic energies, but only the particles colliding with more energy than the activation energy of the reaction causes the rate of the reaction to increase."

Correct me if i'm wrong, but isn't it the particles with energy "equal to or greater than the activation energy"?

I think you're correct.

[stonecold]

Just remember the difference between rate and equilibrium.

For and endothermic reaction, increasing the temperature is ideal as it will both increase the reaction rate, and shift the equilibrium to the right.

However, for exothermic reactions (which are the most common), increasing the temperature will indeed increase the rate of reaction, as the number of collisions and therefore 'successful collisions' (particles colliding with sufficient kinetic energy and at the correct orientation are deemed 'successful') will increase, however, the reverse reaction will be favoured by this increase in temperature (as it is endothermic), so the equilibrium will shift to the left, and the yield will be decreased.

This is not what is desired in industry, therefore other measures such as the addition of a catalyst are used.  If a high temperature is maintained, then the system may be opened so that the products can escape and the reverse reaction cannot proceed.

Pressure/concentration can also be used to shift the equilibrium, but it depends on the particular reaction as to whether it will cause a shift to the left or the right.

[tram]

yea, but i think the original question is just foucssing on rates....

but yea, everything you said is compeltely true

[stonecold]

Yeah, I just wanted to make it clear, because I can see people thinking that increasing the temp will automatically increase the reaction rate (true) and hence the yield, which is wrong.

[tram]

yea very very tru, lol, our teacher made a point of making that distinction

[98.40_for_sure]

Yep, but the prac is solely on Rates of reactions, so i didn't think it was necessary to mention anything about equilibrium

[Martoman]

The sac for both concentration and tempterature we did at school was a joke.

Draw a  graph.

What is the effect of conc/temp on rate?

Why?

Errors