Lecture 4,5,6 - Thermodynamics and Bioenergetics Flashcards
What is a system
The part of the universe that is of interest
What is a surrounding
Everything outside of a specified system
What is a boundary
a closed 3d surface that separates the system from its surroundings
What is a process
When thermodynamic state of a system is changed
What is the first law of thermodynamics
Energy can neither be created nor destroyed, but it can be transferred
What is enthalpy change
The heat change of a reaction at constant pressure
(slide 7 !! read equation)
What is a closed system (in thermodynamics)
can exchange energy (as heat or work) but not matter, with its surroundings
What can be transferred in a thermodynamic system
Heat (q)
Work (w)
What is the second law of thermodynamics
Any spontaneous process must cause the entropy of the universe to increase
What is entropy (S) (slide 8)
The measure of the degree of disorder or randomness in a system
Is enthalpy change indépendant of pathway?
Yes (doesn’t matter if we go ABC or ADC)
What do molecules in a system have a natural tendency towards?
Randomisation
(S system + S surroundings = maximal)
What is the equation for enthalpy change
DH = DU + PDV
What Is enthalpy
The total energy content of a system
What is an open system
A system that exchanges both matter and energy with its surroundings
