Difference between the two following formulas

  • Context: Undergrad 
  • Thread starter Thread starter Kibz665
  • Start date Start date
  • Tags Tags
    Difference Formulas
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
Sign up Log in
3 replies · 1K views
Kibz665
Messages
2
Reaction score
0
Can some one please tell me what is the difference between the two following formulas and when it is used:
dQ=dU+dW
dU=dQ+dW
 
Physics news on Phys.org
Are you asking about the different conventions used by physicists and chemists for the 1st law..?
 
Kibz665 said:
Can some one please tell me what is the difference between the two following formulas and when it is used:
dQ=dU+dW
dU=dQ+dW
In the first equation, dW represents the work done by the system on the surroundings. In the second equation, dW represents the work done by the surroundings on the system. Both conventions are used, depending on the author.
 
Thanks that was very helpful.
 

Similar threads

Undergrad First law of thermodynamics -- two different expressions for dQ
  • laser1
  • · Replies 23 ·
  • Thermodynamics
Replies
23
Undergrad Confusion on Callen's Maximum Work Theorem
  • EE18
  • · Replies 7 ·
  • Thermodynamics
Replies
7
Undergrad Graphical difference between adiabatic and isothermal processes.
  • zenterix
  • · Replies 1 ·
  • Thermodynamics
Replies
1
What is ##Tds## in this equation : ##dU = Tds - PdV##
  • MatinSAR
  • · Replies 14 ·
  • Introductory Physics Homework Help
Replies
14
Undergrad Answer: Is My Logic Correct: Reversible Processes & Heat Transfer?
  • Rohit93
  • · Replies 1 ·
  • Thermodynamics
Replies
1
Undergrad Why is ##dQ = dH## still valid for chemical reaction (Callen)?
  • EE18
  • · Replies 31 ·
  • Thermodynamics
2
Replies
31
Undergrad How to measure average thermal conductivity of a metallic material?
  • zenterix
  • · Replies 1 ·
  • Thermodynamics
Replies
1
Undergrad Liquids, internal energy and specific heat capacity
  • metalrose
  • · Replies 4 ·
  • Thermodynamics
Replies
4
Undergrad I can’t understand the derivation of the formula Cp=Cv+nR
  • Clara Chung
  • · Replies 4 ·
  • Thermodynamics
Replies
4
Graduate Confused about use of external vs internal pressure in thermodynamics
  • etotheipi
  • · Replies 13 ·
  • Thermodynamics
Replies
13