Work against the external pressure

  • Thread starter Thread starter omni
  • Start date Start date
  • Tags Tags
    Pressure Work
Click For Summary
SUMMARY

The discussion centers on calculating the work done against external pressure during the reaction of nitrogen and hydrogen to form ammonia. The formula W = -PexΔV is identified as essential for this calculation, with Pex set at -1 atm (equivalent to -101,325 Pa). Participants highlight the need to determine the change in volume (ΔV) to proceed, suggesting the ideal gas law (PV = nRT) as a potential method to find the necessary volumes for the calculation. The reaction is confirmed to be exothermic, which may influence the volume change.

PREREQUISITES
  • Understanding of the ideal gas law (PV = nRT)
  • Knowledge of chemical reaction stoichiometry
  • Familiarity with thermodynamics concepts, particularly work and pressure
  • Basic understanding of exothermic and endothermic reactions
NEXT STEPS
  • Calculate ΔV using the ideal gas law (PV = nRT) for the ammonia reaction
  • Explore the implications of exothermic reactions on gas volume changes
  • Investigate the relationship between pressure, volume, and work in thermodynamic processes
  • Review the concept of standard conditions for gas reactions (1 atm, 25°C)
USEFUL FOR

Chemistry students, chemical engineers, and anyone studying thermodynamics and reaction kinetics will benefit from this discussion.

omni
Messages
192
Reaction score
1
in the picture you can see the reaction.

it's known that 2 mol nitrogen reaction with 6 mol hydrogen gas to create ammonia.
what is the work against the external pressure in 1 Atm in 25 degrees Celsius?

i think i need to use this formula:W=-PexdeltaV.
but i can't know what is deltaV.

i just know that -Pex=-1atm. 1atm=101,325 Pa
and is a exothermic reaction.

how can i keep on from here?

thanks.
 

Attachments

  • 111.JPG
    111.JPG
    3.9 KB · Views: 420
Physics news on Phys.org
ΔV is just a volume change - what is an initial volume? What is a final volume?
 
Is not given in the description question.
maybe i can use PV=nRT?
and from this formula i can find V?

what are you think?
and just to be sure W is what i need to find yes?

thanks.
 

Similar threads

Chemistry Finding rate constant from pressure change in an experiment
  • · Replies 2 ·
Replies
2
Views
2K
What Is the Concept Behind Finding Mole Fraction in Gas Absorption Problems?
  • · Replies 10 ·
Replies
10
Views
3K
What is the partial pressure of ammonia at equilibrium?
  • · Replies 2 ·
Replies
2
Views
2K
Calculating Entropy Change for an Ideal Gas Expansion
  • · Replies 7 ·
Replies
7
Views
3K
Pressure-Volume Work
  • · Replies 7 ·
Replies
7
Views
1K
Thermodynamic Problem: Ideal Gas Expansion and Work Calculation
  • · Replies 16 ·
Replies
16
Views
3K
How many grams of Zn reacted in this reaction (very easy chemistry question)
  • · Replies 5 ·
Replies
5
Views
16K
Expansion of a gas at constant temperature and pressure
  • · Replies 1 ·
Replies
1
Views
8K
Chemistry homework help with enthelpy
  • · Replies 3 ·
Replies
3
Views
2K
Final Pressure of Gas Mixture After Reaction Completed
  • · Replies 10 ·
Replies
10
Views
5K