thermodynamics Flashcards
energy must be conserved.. but..
can take different forms
entropy
a measure of a systems disorder and tends to increase
what is free energy change determined by
the change in enthalpy and entropy
free energy must be negative…
for a reaction to be spontaneous
what are: open systems that constantly exchanged matter and energy with their surroundings
organisms
what do enzymes do
increase the rates of thermodynamically favourable reactions
the universe can be divided into two sections
system
everything else
system
what can be controlled
everything else
the surroundings
closed system
only allows energy and work
isolated systems
no transfer of matter, energy or work across boundary
open systems
transfer of matter, energy and work across the boundary
we usually use..
closed system, where only work and energy can cross the boundary
whether a reaction absorb or releases hat cannot predict…
whether the reaction will happen or not, therefore we must look to entropy
first law of thermodynamics
‘energy can neither be created or destroyed’
-the change in the internal energy of a closed thermodynamic system is equal to the sum of work done on the system and the amount of heat energy supplied to the system.
the change in the internal energy of a closed thermodynamic system is equal to..
the sum of work done on the system and the amount of heat energy supplied to the system
most spontaneous reactions…
release internal energy
when a system undergoes change: but these into an equation: deltaU= Q-W
u= internal energy of the system; Q=heat put into the system, W= work done ; delta= indicates change
deltaU= Q-W
or
deltaU=U(final)- U(initial)
second law of thermodynamics
the total entropy of any isolated thermodynamic system tends to increase over time
entropy basics
- measure of disorder of a system
- the ‘ordileness’ of a system is related to how likely an arrangement is to happen by chancr–> the more ways this could happen by chance- the greater the disorder
the higher the entropy
the more disordered
part of the second law is the..
law of statistics- with enough molecules- stats become inevitable
deltaG
gibbs free energy
gibbs free energy
combines both the change in entropy in a closed system, and the disorder added to the environment by the hear into a single function
gibbs equation
deltaG=deltaH-TdeltaS
to be spontaneous a reaction deltaG must be..
negative or equal to zero
how com life is well ordered and operates a long way from equilibrium
due to coupled reactions
how do coupled reactions make life more ordered and predictable
extremely favourable reactions are coupled (free energy is much smaller than zero) with extremely unfavourable reactions (free energy is more than 0)
-relies on the reverse of the unfavourable reaction being very slow in the cell
example of where cells maintains pools of accessible, favourable reactions that can be used to drive other reactions
eg. the hydrolysis of ATP= -31jKmol-1
