How Does a Small Sample of Gas Exert Great Force on a Cube's Faces?

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Homework Help Overview

The problem involves a cube containing air at atmospheric pressure and a specified temperature, with questions regarding the mass of the gas, its weight, the force exerted on the cube's faces, and a commentary on why a small sample can exert a significant force.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the application of the ideal gas law and the relationships between pressure, volume, and force. There are attempts to calculate mass and force, with questions about the conversion of pressure units and the implications of the results.

Discussion Status

Some participants have provided calculations and expressed confidence in their results, while others are seeking clarification on the underlying physical principles. The discussion is ongoing, with various interpretations being explored regarding the physical reasoning behind the force exerted by the gas.

Contextual Notes

There is a focus on the assumptions related to the behavior of gas molecules and their interactions with the cube's surfaces, as well as the need to understand the implications of the calculated force in relation to the sample size.

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Homework Statement



A cube 10.0 cm on each edge contains air ( with equivalent molar mass 28.9 gm/mol ) at
atmospheric pressure and temperature 300K. Find (a) the mass of the gas, (b) its weight,
(c) the force it exerts on each face of the cube. (d) Comment on the underlying physical reason why such a small sample can exert such a great force.


( I know it is simple quastion but i want to sure from my answer )

please i need the answer today

best wishes for you
 
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You will need the ideal gas law:
PV=nRT

Then write down what you know and your unknowns and see where you can go from that?
R is a constant R = 8.314472 J/(K*mol)

your pressure is a known btw, it says it is at atmospheric pressure.
 
ok

i found mass from ideal law

then

weight = mg

ok ?

now force = P * A right ?

p = 1 atm = 1.013 * 10^5 N/m^2 . are u sure ?

then i found F

ok

i need comment please
 
Dr.Wasim said:
p = 1 atm = 1.013 * 10^5 N/m^2 . are u sure ?

I don't understand where your getting this from.
You had the equation right
Force = Pressure * Area.
So just multiply the atmospheric pressure by the area of one face on the cube. which is 100cm^2.
 
p = 1 atm = 1.013 * 10^5 N/m^2 ( Paskal )

it is known for evret one

and we found force in ( Newten ) so we must convert atm to paskal

now i want the answer for

(d) Comment on the underlying physical reason why such a small sample can exert such a great force.
 
re d) what is gas made up of? what is the average velocity of a gas molecule at 300K? How many are banging into the walls at anyone instant? Thats the sort of thing I think is being sought in the answer.
 
i don' what you mean

now see

i found force and it is equal 1013 newten and it is a great force

we have small sample of gas that exert this force on each face of cube

the quastion now ... what is phyiscal reason for that ?
 

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