Chem+Physics: Solving the Piston Puzzle

  • Thread starter Thread starter prinzessin04
  • Start date Start date
  • Tags Tags
    Piston Puzzle
AI Thread Summary
The discussion revolves around a webassign question involving a piston separating hydrogen and helium gases in a cylinder. For part (a), there is confusion about whether the ratio of hydrogen to helium molecules should be 1:1 since the piston is centered. It is clarified that while the pressures are equal, the number of molecules (N) must also be considered, leading to the conclusion that the ratio is indeed 1:1. For part (b), the participant realizes that the question may not be as tricky as initially thought, indicating a better understanding of the concepts involved. Overall, the interaction highlights the challenges of integrating chemistry and physics concepts in problem-solving.
prinzessin04
Messages
5
Reaction score
0
this is my webassign question for this week but I'm a little confused about the first part...
for part a) shouldn't the ratio just be 1 to 1, since the piston is exactly in the center?? or did i understand that wrong? I'm not all that great at chem especially when it comes to chem and physics together...
:eek:

A cylinder closed at both ends has a piston in between that is free to slide. At 22°C, the piston is exactly in the center when hydrogen gas is in one end and helium in the other.

(a) What is the ratio of the number of hydrogen molecules to the number of helium molecules?


(b) Where will the piston be if the temperature is raised to 59°C?
the choices:
in the same place
0.22 L to the left
0.44 L to the right
0.22 L to the right
0.44 L to the left


for part a) shouldn't the ratio just be 1 to 1, since the piston is exactly in the center?? or did i understand that wrong? I'm not all that great at chem especially when it comes to chem and physics together...
 
Physics news on Phys.org
PV=NkT

If the piston is in the center, and it doesn't move, then pressures on both sides are equal. What else must be equal? V? T? N? (yup, yup, yup).

Sometimes it's the simple ones that seem so hard.

Part b) should be easy now.
 
thanks, i just figured the question was trying to trick me like they usually do...
 
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
Back
Top