# l03 - 20.110J 2.772J 5.601J Thermodynamics of Biomolecular...

This preview shows pages 1–4. Sign up to view the full content.

20 .110/5.60 Fall 2005 Lecture #3 page 1 EXPANSIONS, ENERGY, ENTHALPY Isothermal Gas Expansion (0 T ) = gas ( p 1 , V 1 , ) = gas ( 2 , 2 , ) Irreversibly (many ways possible) (1) Set ext = 0 p =0 T p 11 ,V p T p 22 ,V 2 1 (1) 0 v ext wp d = −= (2) Set ext = 2 T p ,V p 2 p 2 T p ,V () 2 1 2 (2) 1 =− - w (2) p p 2 p 1 V 1 V 2 Note, work is negative: system expands against surroundings 20.110J / 2.772J / 5.601J Thermodynamics of Biomolecular Systems Instructors: Linda G. Griffith, Kimberly Hamad-Schifferli, Moungi G. Bawendi, Robert W. Field

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
20 .110/5.60 Fall 2005 Lecture #3 page 2 (3) Carry out change in two steps gas ( p 1 , V 1 , T ) = gas ( 3 , 3 , ) = gas ( 2 , 2 , ) 1 > 3 > 2 T p 11 ,V p 3 p 2 p 22 ,V p 3 T p 33 ,V T ( ) () 32 13 3 3 3 1 (3) vv VV wpd d −− =− = ∫∫ More work delivered to surroundings in this case. - w (3) p p 2 p 1 p 3 V 1 V 2 V 3 (4) Reversible change = ext throughout 2 1 rev wp - p p 2 p 1 V 1 V 2 Maximum work delivered to surroundings for isothermal gas expansion is obtained using a reversible path For ideal gas: = 2 1 ln ln Vp nRT wdV n R 20.110J / 2.772J / 5.601J Thermodynamics of Biomolecular Systems Instructors: Linda G. Griffith, Kimberly Hamad-Schifferli, Moungi G. Bawendi, Robert W. Field
20 .110/5.60 Fall 2005 Lecture #3 page 3 The Internal Energy U dU = q + w (First Law) d - d - ext path dU C dT p dV =− And () , VT UU UTV TV ⎛⎞ ⎜⎟ ⎝⎠ ∂∂ ⇒= + Some frequent constraints: Reversible q rev + = rev – pdV ( ) = d - d - d - Isolated q = w = 0 d - d - Adiabatic q = 0 w -pdV reversible d - d - Constant V V d - T

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 7

l03 - 20.110J 2.772J 5.601J Thermodynamics of Biomolecular...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online