Need any chem master's help..

[willgotoapharmschool]

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How is volume related to temperature in terms of kinetic-molecular theory?
For instance, if the volume of a gas doubles, how can I say that the temperature must have been reduced by half? (#3 in dr. collins chemistry test #13)

🙁 I googled to look for a clear relationship of those two, but I couldn't find any. Thank you in advance!

 

[CofCMarineBiologist]

Disregard

 

[WSUWarrior012]

(V1)(T1)=(V2)(T2)

So say your initial V= 1L and initial temperature T=2......so you said the Volume doubled.....So Volume final V2=2L now plug it the known values.

(1L)(2)=(2L)(T2)

T2=(2)(1)/(2)= 1

So your temperature reduced by half.

Hope that makes sense....

This is the wrong relationship between volume and temperature. The correct formula would be:

(V1/T1) = (V2/T2) aka Charles's law

 

[CofCMarineBiologist]

Good Look. I was thinking Boyle's.

 

[willgotoapharmschool]

This is the wrong relationship between volume and temperature. The correct formula would be:

(V1/T1) = (V2/T2) aka Charles's law

I thought volume and temperature were directly proportional, no :/ ?

 

[WSUWarrior012]

I thought volume and temperature were directly proportional, no :/ ?

They are. Pressure and volume are both directly proportional to temperature while pressure and volume are inversely proportional to each other.

 

[willgotoapharmschool]

They are. Pressure and volume are both directly proportional to temperature while pressure and volume are inversely proportional to each other.

so the problem in dr. collins I mentioned above is wrong? they said if volume doubles, temp must have decreased by 1/2..

 

[Thestrugglez]

What's the exact problem say?

 

[willgotoapharmschool]

According to the kinetic-molecular theory, if the volume of a gas doubles the temperature must have b) been reduced by half. (that is the answer)
I hope I don't get in trouble for putting up the problem..

 

[10pharm7]

According to the kinetic-molecular theory, if the volume of a gas doubles the temperature must have b) been reduced by half. (that is the answer)
I hope I don't get in trouble for putting up the problem..

If volume is increased- Pressure will be decreased so temperature is also reduced.

 

[willgotoapharmschool]

If volume is increased- Pressure will be decreased so temperature is also reduced.

Oh.. so if I want to talk about the relationship between volume and temperature, I need to apply pressure and temperature's relationship on top of boyle's law?
WAIT, then what does Charles's law do?! I thought charles's law states that as temp goes up, volume increases, no?..

 

[Alex_PharmD]

Oh.. so if I want to talk about the relationship between volume and temperature, I need to apply pressure and temperature's relationship on top of boyle's law?
WAIT, then what does Charles's law do?! I thought charles's law states that as temp goes up, volume increases, no?..

Man why you have to make it seem so hard to comprehend just think logicly dont start naming laws and peoples names. What happens when you raise the temperature on gases the pressure increases and if you lower the temperature the pressure decreases knowing that when you double the volume gas has more space to move freely lowering its pressure now compare this to temperature which one also lowers the pressure lowering the temperature. So if they said what does reducing the volume say about the temperature you would suppose that it increased since both would cause a increase in pressure!

You can always refer to the PV/T=PV/T as backup if all else fails by just plugging in numbers related to the question..

 

[willgotoapharmschool]

Man why you have to make it seem so hard to comprehend just think logicly dont start naming laws and peoples names. What happens when you raise the temperature on gases the pressure increases and if you lower the temperature the pressure decreases knowing that when you double the volume gas has more space to move freely lowering its pressure now compare this to temperature which one also lowers the pressure lowering the temperature. So if they said what does reducing the volume say about the temperature you would suppose that it increased since both would cause a increase in pressure!

You can always refer to the PV/T=PV/T as backup if all else fails by just plugging in numbers related to the question..

OHHHHHHHH I get it. The question never said the pressure was constant! I don't know why I just assumed that the pressure had to be constant, so it didn't make any sense. Thank you so much everyone ! 😀

 

[blueheron]

OHHHHHHHH I get it. The question never said the pressure was constant! I don't know why I just assumed that the pressure had to be constant, so it didn't make any sense. Thank you so much everyone ! 😀

The pressure IS constant...

That's why that answer is true...

#whyimthechemist

 

[willgotoapharmschool]

The pressure IS constant...

That's why that answer is true...

#whyimthechemist

If pressure is constant, volume is directly proportional to temperature! ;<