Calculating Gas Pressure: Solving for Pressure in a Variable Volume

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SUMMARY

The discussion focuses on calculating gas pressure using the ideal gas law, specifically the equation p=nRT/V. Given a gas occupying 2m³ at a pressure of 100kPa, the pressure when the volume is reduced to 1.5m³ while maintaining constant temperature is determined to be 133kPa. Participants emphasize the importance of understanding the relationship between pressure and volume, as well as correctly applying the ideal gas law to solve for pressure in different states.

PREREQUISITES
  • Understanding of the ideal gas law (p=nRT/V)
  • Knowledge of pressure and volume relationships in gas laws
  • Familiarity with unit conversions (e.g., from m³ to liters)
  • Basic algebra for manipulating equations
NEXT STEPS
  • Study the derivation and applications of the ideal gas law
  • Learn about Boyle's Law and its implications for pressure and volume
  • Explore real-world applications of gas laws in engineering and physics
  • Practice solving problems involving gas laws with varying conditions
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Students in chemistry or physics, educators teaching gas laws, and professionals in fields requiring gas pressure calculations, such as engineering and environmental science.

Bechensten
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Homework Statement


Gas occupies 2m^3 at a pressure of 100kPa. What is the pressure when the volume is 1.5m^3 and the temprature is unchanged?

Homework Equations


p=nRT/V

The Attempt at a Solution


As a logic conclusion i took 1.5/2x100 and got 75 but 175 is not the answer.. The answer is 133kPa.
I also tried the p=nRT/V.
22.4l=1mol so 1500/22.4x1 is 66.96mol. (66.96x22.4x0)/1500=0
Can someone please tell me how to calculate this type of problem?

Thank you.
 
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Bechensten said:

Homework Statement


Gas occupies 2m^3 at a pressure of 100kPa. What is the pressure when the volume is 1.5m^3 and the temprature is unchanged?

Homework Equations


p=nRT/V

The Attempt at a Solution


As a logic conclusion i took 1.5/2x100 and got 75 but 175 is not the answer.. The answer is 133kPa.
I also tried the p=nRT/V.
22.4l=1mol so 1500/22.4x1 is 66.96mol. (66.96x22.4x0)/1500=0
Can someone please tell me how to calculate this type of problem?

Thank you.
Well, your "logic conclusion" got warped somehow.

If you take a certain volume of gas and then shrink that volume, keeping the amount of gas and its temperature constant, what do you think happens to the pressure of the gas confined into that new, smaller volume?

If you analyze the relation PV = nRT, n is the same, R is a constant, and T is the same. So what happens to PV if V gets smaller?
 
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Bechensten said:

Homework Statement


Gas occupies 2m^3 at a pressure of 100kPa. What is the pressure when the volume is 1.5m^3 and the temprature is unchanged?

Homework Equations


p=nRT/V

The Attempt at a Solution


As a logic conclusion i took 1.5/2x100 and got 75 but 175 is not the answer.. The answer is 133kPa.
I also tried the p=nRT/V.
22.4l=1mol so 1500/22.4x1 is 66.96mol. (66.96x22.4x0)/1500=0
Can someone please tell me how to calculate this type of problem?

Thank you.

Always check your units to make sure that what you are calculating makes sense.
You are analyzing the gas in two states.
Start with what you know. What is the pressure and volume of the gas in the first state? What do you know about the second state? I would encourage you to use subscripts. P1 is the pressure of the gas in state 1. P2 is the pressure of the gas in state 2. V1 is the volume of the gas in state 1. etc.
 
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