Change in GIbbs free energy for ethanol

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SUMMARY

The discussion focuses on calculating the change in Gibbs free energy (ΔG) for 35g of ethanol when the pressure is increased isothermally from 1 atm to 3000 atm. The correct formula used is ΔG = VΔP, where V is the volume of ethanol calculated using its density of 0.789 g/cm³. The volume is determined to be approximately 44.4 cm³, leading to a ΔG value of 10.4 kJ when the pressure change is applied. Participants confirm the necessity of converting all units to SI for accurate calculations.

PREREQUISITES
  • Understanding of Gibbs free energy and its significance in thermodynamics
  • Familiarity with the equation ΔG = VΔP
  • Knowledge of unit conversions, particularly between atm, Pa, and SI units
  • Basic principles of density and volume calculations
NEXT STEPS
  • Learn about the implications of Gibbs free energy in chemical reactions
  • Study unit conversion techniques for pressure and volume in thermodynamic calculations
  • Explore the relationship between pressure, volume, and temperature in isothermal processes
  • Investigate the properties of ethanol and its behavior under varying pressure conditions
USEFUL FOR

Chemistry students, thermodynamics enthusiasts, and professionals involved in chemical engineering or physical chemistry who seek to deepen their understanding of Gibbs free energy calculations.

koomanchoo
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hey i seem to be having a lot of trouble with this type of question:
Calculate the change in Gibbs energy of 35g of ethanol (mass density = 0.789g cm-3) when the pressure is increased isothermally from 1 atm to 3000 atm.

in my notes i have that dG=V(Pf-Pi) and search up on the net that mass=volume*density so volume of ethanol comes to 35/.789 the answer is suppose to be 10.4kJ but i get nowhere near it.

dG=(35/.789)*(3000-1) is this the right equation because that's all i can find
pls help me! thanks
P.K
 
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Okay.Maybe

\Delta G=V\Delta p

sounds right.I'm sure you need to convert all units into SI-mKgs.

1 atm=101,325 Pa
1 cm^{3}=10^{-6}m^{3}

1kJ=1000J

Daniel.
 
thanks man

Thanks heeeeeeeeeaps! Daniel :biggrin:
you made my day. spent ages doing that Q like hours and hours just seraching what i was doing wrong. thanks again.
this forum rOcks!
:approve:
 
Please,do not double post.You should have asked it in one single forum.I think Classical Physics was the appropiate choice...

Daniel.
 

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