Combined Gas Law: Find Volume V2

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Homework Help Overview

The discussion revolves around the Combined Gas Law, specifically focusing on determining the volume (V2) under varying pressure (P1, P2) and temperature (T1, T2) conditions. Participants are analyzing the implications of given values and their units in the context of gas behavior.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants are questioning the representation of temperature and pressure values, particularly the need to convert temperature to Kelvin and the ambiguity of pressure units (psia vs. psig). Some are exploring the effects of pressure and temperature changes on volume.

Discussion Status

There is a range of interpretations regarding the initial conditions and calculations. Some participants have shared their results and assumptions, while others express confusion about the problem's setup. Guidance has been offered regarding unit conversions and clarifications on the pressure context.

Contextual Notes

Participants note the ambiguity in the pressure measurement and the necessity of converting temperature to Kelvin, which could affect their calculations. There is also mention of the problem potentially being designed to differentiate between varying levels of student understanding.

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Homework Statement
1.1L volume O2 collected in balloon, at 295K, 13.6 psi.
next day... 32C, 0.98 atm
what is the volume in the balloon.

a) 0.107L
b) 1.07L
c) 10.7L
d) 107.0L
Relevant Equations
pv/t = pv/t
1atm = 14.7psi
P1= 13.6 V1= 1.1 T1= 22 P2 = 14.4 V2= x T2 = 32
my answer is 1.51L

am i missing something? 
 
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Yes, an explanation what the numbers represent. Hint: 22 is NOT T1 in your relevant equation.
 
Damn! I need to convert to Kelvin for gas problems, right
 
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"13.6 psi" in the problem statement is ambiguous. Is that psia or psig? Doubly confusing since a "balloon" suggests pressure higher than ambient. You can work out the answer both ways and then see whether the available choices allow you to eliminate one possibility. I call that a crummy question.
 
Does increasing the pressure cause the volume to decrease or increase?

Does decreasing the temperature cause the volume to decrease or increase?
 
I get none of the answers that are given.
 
I got (b) 1.07 liter by assuming the 13.6 psi initial condition is psia. Also note, the initial volume is 1.1 liters; I missed that the first time thru (thinking it was 1 liters).
 
gmax137 said:
I got (b) 1.07 liter by assuming the 13.6 psi initial condition is psia. Also note, the initial volume is 1.1 liters; I missed that the first time thru (thinking it was 1 liters).
I also got 1.07 now. Initially I used 293 instead of 305 for some reason.
 
Last edited:
thanks for the answers, i am happy with what i have... i am now sure the question is designed to dilineate two levels of students, and so there's no need for me to progress further for now.
 

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