2) Principles Of Thermodynamics Flashcards
Subject of thermodynamics
Thermodynamics studies the conversions of energy exchanges between systems as heat and work
Biological thermodynamics studies the general always of energy conversion in living systems
Thermodynamic bodies and systems
thermodynamic body
Is a very large ensemble of particles
Thermodynamic system
Is a set of thermodynamic bodies exchanging energy
Types of thermodynamic systems
Isolated
Do not exchange matter and energy with environment
Closed
Exchange energy but not matter
Open
Exchange energy and matter with the environment
Thermodynamic variables
Properties characterising the thermodynamic systems
Eg: volume, pressure and mass
Thermodynamic state
The set of instaneous values of the thermodynamic variables of a system
The state changes if any of the variables change
Types of thermodynamic states
Equilibrium state
All the thermodynamic variables of the system remain constant and have the same value for all points In the system
Non equilibrium state
The variables have different values at different points in the system and change over time
Graphic representation of thermodynamic states
Y is p
X is v
Half way of y is pa
Half way of x is va
Both points meet at a
Can be represented using a pressure and volume diagram
Equation of state
An equilibrium state is determined by pressure, volume, temp and amount of substances in a system
F(p,v,T,n) =0
Thermodynamic process
Is the transition of a thermodynamic system from one state to another
Types of thermodynamic processes is
Equilibrium system is always in equilibrium and is show
Non eq is when the process will run with finite speed
Graphic representation of thermodynamic process
Y is p
X is v
Curved line from A to B in the middle of graph
Equilibrium process is represented by a curved graph on the pv diagram
Non eq cannot be represented on pv
Thermodynamic potentail
Variable of thermodynamic system where the changes depend on the initial and final stages only
Same as the second graph but it forms like a 0 I’ve line above and one below with arrow pointing to B
Internal energy
Is a thermodynamic potential
Does not depend on the movement or position of the system as a whole
The total potential energy associated with the inter atomic and inner molecular forces
Work
This is the energy transferred can be described as the fb ages of a macroscopic system
Has performs work when expanding against force
Heat
Is a form of energy transfer that changes the microscopic thermal motions of particles
Energy changes
Heat exchanges only alter the internal energy
First principle of thermodynamics
Law about energy conservation in thermodynamics
&Q=du+&A
Amount of heat transferred to the system &Q
Is used to increase internal energy of system by dU and performs work &A on the environment
Enthalpy
When system changes it’s volume dv at constant pressure P the work performed by the system is
&A=p.dV
Hess law
Same drawing but Ha and Hb
The thermal effect does not spend not be late taken from reactants to products. It will be the same regardless of path
Applications
Used to calculate the energy content of food
Calculate the enthalpy of complex biochemical cycles
Source of energy for human body
The human body uses chemical energy from food released in oxidation morning
Types of work in the human body
Chemical reactions
Mechanical
Movement of body parts and loads
Osmotic
Transport of substances from areas of low concentration to high
Electric
That transport of charged particles and generation on biopotentials
Types of heat in the human body
Primary is produced by metabolic and other processes in the body
Secondary
Some of the useful work is converted into heat
Regulation of heat production in the body
Control primary heat production rate
When body is cooled the metabolic process shifts to follow less efficient rout
Control secondary heat production route
Shivering
Biological systems and fist principle of thermodynamics
The body must balance inputs and outputs of energy
The body must receive energy from the environment in the form of food products
All work is performed with the same amount on energy being extracted from food
