Thermo Lecture 1 Flashcards
What are the 2 manifestations of energy?
- Can be freely and fully converted into other types
2. Thermal. Cannot be fully converted
What is ‘Energy Dissipation’?
The conversion of non-thermal energy to heat
What is the Equation for work?
- dW = F dx
2. dW = -PdV
What are the units of work?
J
kg m^2 s^-2
What is an open system?
Where mass transfer can occur between the system & surroundings
What is a closed system?
Where there is NO mass transfer but energy can flow as work or heat
What is an isolated system?
Where there is no mass or energy transfer
What is expansion work?
Energy transfer that has resulted in a change of volume. The expanding substance is going mechanical work on its surroundings
What is a reversible process?
One which moves through a series of equilibrium states and therefor is no energy dissipation (as head) as the process proceeds
What does ‘quasi-static’ mean?
Proceeding though a series of equilibrium states, reaction is slow enough to keep system in internal equilibrium
What is an adiabatic system?
A process or system in which no heat is transferred between system and surroundings. No energy dissipation.
What is the Ideal Gas EOS
PV = nRT
What are the assumptions of the Ideal Gas EOS?
- Vol occupied by molecules «_space;Vol occupied by gas
- No intermolecular forces
- Collisions between molecules elastic
Equation for Kt?
Kt = -V(dP/dV)t
Equation for βt?
1/Kt
Equation for α?
1/V(dV/dT)p
Define ‘phase’?
The physically distinguishable subsets of a system
Define ‘extensive’ properties
Properties dependent on the amount of a substance
Define ‘intensive’ properties
Properties independent on the amount of a substance e.g. P & T
What are state functions?
Properties that define the state of a system?
They are independent of path, are exact differentials and are in a closed cycle.
What is Heat Capacity, C?
C = dQ/dT
The heat absorbed by a system over the resultant temperature rise
Why does a system of constant volume yield a greater temperature increase than one with constant pressure ?
Because when constant P some heat used for expansion work in addition to temperature rise
What does the zeroth Law of Thermodynamics state?
T is a state function
