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In summary, the conversation discusses a closed system consisting of 2 lb of gas undergoing a process where pV^n=constant. The values for p and V at states 1 and 2 are provided. The conversation also touches on finding the value of n, the specific volume at states 1 and 2, and how to sketch the process on pressure-volume coordinates. The units for pressure and mass are mentioned as well.

- #1

Saladsamurai

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## Homework Statement

A closed system consisting of 2 lb of a gas undergoes a process in which pV^n=constant. For: p1=20 lb/in^2 , V1=10 ft^3 and p2=100lb/in^2 V2=2.9 ft^3

(a)What is *n* ?

(b)What is the specific volume at states 1 and 2 in ft^3/lb?

(c)Sketch the process on pressure-volume coordinates

For (a), I don't need to convert the units all to feet or all to inches right? i can just say p1V1^n=p2V2^n correct?

(b) Is just a matter of find the mass m=Weight/g

(c) Is confusing me? Is this just a graph? With p on the horizontal axis and V on the vertical?

Thanks!

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- #2

Saladsamurai

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Okay, I got (a)...the units cancel anyway.

But for (b) I cannot tell if they are giving me 2lb as a mass or as a weight. It's a thermodynamics book, so I don't know what the convention is? they did not specify lbf (force) or lbm (mass)

- #3

Andrew Mason

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Saladsamurai said:

## Homework Statement

A closed system consisting of 2 lb of a gas undergoes a process in which pV^n=constant. For: p1=20 lb/in^2 , V1=10 ft^3 and p2=100lb/in^2 V2=2.9 ft^3

(a)What is

n?(b)What is the specific volume at states 1 and 2 in ft^3/lb?

(c)Sketch the process on pressure-volume coordinates

For (a), I don't need to convert the units all to feet or all to inches right? i can just say p1V1^n=p2V2^n correct?

Correct.

[tex]P_1V_1^n = 5P_1(.29V_1)^n[/tex]

(b) Is just a matter of find the mass m=Weight/g

Correct

(c) Is confusing me? Is this just a graph? With p on the horizontal axis and V on the vertical?

You have to plot points in between the end points as well.

AM

- #4

Andrew Mason

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Saladsamurai said:

Okay, I got (a)...the units cancel anyway.

But for (b) I cannot tell if they are giving me 2lb as a mass or as a weight. It's a thermodynamics book, so I don't know what the convention is? they did not specify lbf (force) or lbm (mass)

Are the units of pressure Force/area or mass/area?

AM

## FAQ: What Is the Value of n in the Gas Law Equation for a Given Process?

## What is PV^n=constant?

PV^n=constant is a mathematical equation that represents the relationship between pressure (P) and volume (V) of a gas at a constant temperature. This equation is known as Boyle's Law.

## What does the "n" represent in PV^n=constant?

The "n" in PV^n=constant represents a constant value known as the number of moles. This value is used to convert between the number of particles and the volume of the gas.

## How is PV^n=constant used in science?

PV^n=constant is used in science to understand the behavior of gases at different pressures and volumes. It is often used in experiments to calculate the change in volume or pressure of a gas when one of these variables is altered.

## What are the units for pressure and volume in PV^n=constant?

The units for pressure are typically measured in pascals (Pa) or atmospheres (atm), while volume is measured in cubic meters (m^3) or liters (L).

## What are the limitations of PV^n=constant?

PV^n=constant is only applicable to ideal gases and does not take into account factors such as intermolecular forces and temperature. It also assumes that the number of moles of gas remains constant throughout the experiment.

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