thermodynamics Flashcards
The amount of heat absorbed when CO2 gas reacts with a solid CaO to form solid CaCO3 is measud in a bomb calorimeter. The data obtained give a direct measure of
delta U
It is defined as the fraction of 1/273.16 of the temperature of the triple point of water.
kelvin
Heat required to raise the temperature one pound mass of a substance by degree Farenheit
BTU
Which of the following physical quantities is NOT conserved in a given process
a. momentum. b.energy. c. electric charge. d.entropy
entropy
During adiabatic expansion of an ideal gas, work is done by the system and its internal energy
decreases
All of the following have standard enthalpy of formation values equal to zero at 25 deg C EXCEPT
a. Cl2(g). b. O2(g). c. Na(g). d. N2(g)
Cl2 (g)
The work that may be performed on a system is _______ when the opposing pressure differs only infinitesimally from the internal pressure of the gas itself
minimum
A sample of an ideal is allowed to escape reversibly and isothermally into a vacuum
W=Q=DeltaU=0
A thermodynamic cycle that operates two isothermal and two isentropic processes
Carnot Cycle
The natural flow of heat is described in the statement of
Clausius
If the forward reaction is observed to be spontaneous, which of the ff is possible if its reverse reaction is spontaneous at high temperature?
a. deltaH (+) and delta S (+). c. deltaH (-) and delta S (-)
b. deltaH (+) and delta S (-). d.deltaH (-) and delta S (+)
c. deltaH (-) and delta S (-)
The thermal efficiency is greatly influenced by compression ratio and the specific heat ratio of the working fluid.
Otto Cycle
In rankine cycle, the condition of steam leaving the turbine could be any one of the ff EXCEPT
a. superheated vapor. c. L-V mixture
b. saturated vapor. d. saturated liquid
d. saturated liquid
A physical science that deals with the study of the interrelation of various forms of energy. It is concerned with the transfer of heat and work in various physical and chemical processes.
Thermodynamics
portion of the universe under consideration.
System
Three types of thermodynamics system
- Open system
- Closed system
- Isolated system
It is also called control volume which allows transfer of both matter and energy.
Open system
A type of system that allows neither transfer of matter nor energy.
Isolated system
A type of system also kown as control mass which allows exchange of energy only, consists of a fixed amount of mass while its volume does not have to be fixed.
Closed system
A portion of the universe other than the system.
Surroundings
real/imaginary or fixed/moving surface that separates the system from its surroundings and where exchange of matter or energy takes place.
Boundary
A thermally-conducting boundary in which a change of state is observed even through two objects of different temperatures are brought into contact.
Diathermic boundary
A thermally-insulating boundary in which a change of state is observed even through two objects at different temperatures are brought into contact.
Adiabatic boundary
A state in which the properties of the system does not vary with time. The system is uniform where there is no internal temperature, psssure, concentration or velocity gradient.
equilibrium state
State that exist between two subsystems of equal pressure.
Mechanical equilibrium
The net flows of heat, mass or work between the system and its surroundings is zero and the net rate of all chemical reactions is zero,
Equilibrium state