Molecular interpretation of temperature

AI Thread Summary
The discussion centers on understanding the relationship between molecular speed (vrms) and temperature in the context of gas physics. A specific problem involves determining the temperature increase needed to raise the rms speed of gas molecules by 1% from an initial temperature of 20 degrees Celsius. Participants explore relevant equations, including vrms = √(3kT/m), and discuss how to manipulate these equations to derive the desired results. There is also a conceptual challenge regarding proving the equation vrms = √(P/ρ), where pressure (P) and density (ρ) are involved, leading to confusion about integrating different variables. The conversation highlights the need for clarity in applying physics principles and equations to solve problems effectively.
thattgirljoyy
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i'm trying to do my ap physics summer work, but I've been having a hard time trying to teach this to myself. i do really well in class, but i need a little bit of guidance to help explain how to use the equations the right way.

i'm currently stuck on a question about vrms an it's relation to temp.

Homework Statement


the rms speed of molecules in a gas at 20degrees celsius is to be raised by 1%. To what temperature must it be raised?

Homework Equations


vrms= √3kT/m

The Attempt at a Solution


i don't have any clue where to start if it didn't give me the gas to find it's mass.-i was wondering if i could find someone who could maybe stay in touch for a day or two so i can reach out if i get stuck on anything
 
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What happens to constants when you need a ratio?
 
okay, the temperature would change by sqrt 2, right ?
essentially about 6 degrees kelvin.

i'm stuck on another problem, it seems to be more conceptual.
it says to prove how
vrms=√P/ρ
P, pressure
ρ, density of the gas

i started with the two equations
P=1/3Nmv^2/V
v^2=3KT/m

i assumed the goal was to get the V from the first equation into the denominator of the second to try to get the density (m/v)
some how all I've gotten to was
P/ρ=[3KT(1/3)N]/m

i'm trying to see if i can get the original 3KT/m to revert back to v^2, but i don't know how to get rid of the (1/3)N/m
 
Welcome to PF, thattgirljoyy! :smile:

thattgirljoyy said:
okay, the temperature would change by sqrt 2, right ?
essentially about 6 degrees kelvin.

It's not too far off 6 degrees... but there is no sqrt 2 involved that I can see... :confused:

Let's put it in formulas:
Before you have some unknown vrms,before at 20 degrees Celsius, or 393 K.
Afterward you have vrms,after=1.01vrms,before at some unknown temperature T.
Substitute and solve for T?
i'm stuck on another problem, it seems to be more conceptual.
it says to prove how
vrms=√P/ρ
P, pressure
ρ, density of the gas

i started with the two equations
P=1/3Nmv^2/V
v^2=3KT/m

i assumed the goal was to get the V from the first equation into the denominator of the second to try to get the density (m/v)
some how all I've gotten to was
P/ρ=[3KT(1/3)N]/m

i'm trying to see if i can get the original 3KT/m to revert back to v^2, but i don't know how to get rid of the (1/3)N/m

Did you consider that m is the mass of one molecule?
What is the mass of all molecules in the volume V?
 
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