Primary Word |
Secondary Word |
Definition |
Tutorial Page Link |
partial pressure | For each species in a gas phase, it is the fraction of the total pressure that is caused by the presence of that species. If all of the other type of molecules were removed from the vessel, the final pressure would be the partial pressure of the remaining species. | 2D1 , 2 , 4 , 5 , 6 , 8 , 9 | |
partially miscible | 2A6 | ||
Pascal | 1D2 | ||
path | The actual series of states that the system passes through as it moves from the initial state to the final state during a process. | 3D3, 4A17, | |
path equation | 4A17 - 18 | ||
path variable | 4A8 , 12 , 13, 4B3, 4C5 , 6 | ||
perpetual motion machine | 6C10 | ||
perpetual motion machine | first kind | 6C10 | |
perpetual motion machine | second kind | 6C10 | |
perpetual motion machine | third kind | 6C10 | |
phase | 2A3 - 10 | ||
phase change | 2A4 , 8 , 10 | ||
phase diagram | A plot of one intensive variable against another intensive variable. The intensive variables are often, but not always, P, V or T. A Phase Diagram is useful because it shows what phase will exist for given values of the two intensive variables plotted on the axes. A Phase Diagram also presents curves along which phase transitions occur. PV Diagram, PT Diagrams and TV Diagrams are discussed in this program. | 2B1, 7B1, | |
phase equilibrium | In a system at Phase Equilibrium, the rate at which molecules are making the transition OUT of each and every phase is exactly equal to the rate at which molecules are making the transition INTO the same phase. | 2A9 | |
pipe | 5C6 , 18 | ||
piston-and-cylinder device | 1C2, 2A10, 4A1 , 9 | ||
Pitzer accentric factor | A property of the molecule of a given species that reflects the symmetry of the geometry of a molecule as well as its electrical polarity. | 2F3 | |
polytropic process | A process in which the volume and pressure of a system are related by an equation of the form: PV^n = C , where C and n are constants. | 4A17 , 19, 7A1, 7E7 | |
polytropic process | ideal gas | 7E8 | |
polytropic process | internally reversible boundary work | 7E14 , 15 | |
polytropic process | internally reversible boundary work, ideal gas | 7E16 - 19 | |
polytropic process | logarithmic TS diagram | 7E9 - 13 | |
polytropic process | PV diagram | 8B11 | |
polytropic process | relationship to isentropic process | 7E7 | |
polytropic process | semi-logarithmic PV diagram | 7E9 - 13 | |
polytropic process | shaft work | 8B12 - 20 | |
polytropic process | shaft work on a PV diagram | 8B19 | |
polytropic process | shaft work, ideal gas | 8B14 | |
polytropic process | shaft work, ideal gas, constant heat capacities | 8B15 | |
polytropic process | shaft work, ideal gas, exponent = 1 | 8B16 | |
polytropic process | shaft work, ideal gas, isochoric | 8B18 | |
polytropic process | shaft work, ideal gas, isothermal process | 8B17 | |
potential energy | The energy of a piece of matter associated with the position of the matter within a potential field. The field is usually gravitational. | 1A4, 5B3 , 4, 5E5 | |
pound | force | 1B5 | |
pound | mass | 1B4 , 5 | |
pound mole | 1B4 | ||
power | The rate at which the energy of a system changes or the rate at which energy is teansferred. Power has units of energy per time, such as J/s (Watts) or Btu/h | 4A6 | |
power cycle | A cycle in which energy, in the form of heat, is transferred from a hot reservoir into a system in order to do work on the surroundings. | 4F1 , 3 - 6 | |
power cycle | gas | 4F3, 9E1 - 13, | |
power cycle | gas, closed | 9E2 , 3 , 5 - 13 | |
power cycle | gas, open | 9E2 - 4 | |
power cycle | thermal efficiency | A measure of the performance of a power cycle. Thermal Efficiency is the ratio of the work produced by the cycle to the heat transferred into the heat engine from the hot reservoir. | 4F6, 6B4, 6C4 , 5 |
power cycle | vapor | 9B1 | |
pressure | Force per unit area. In the context of thermodynamics, the pressure force is generally exerted by a fluid (gas or liquid) on a solid surface. The pressure force is due to the sum of all the random collisions of fluid molecules with the solid surface. [ atm, kPa, bar, psi, etc. ] | 1D2 , 3 | |
pressure | absolute | The pressure measured relative to a vacuum (absolute zero pressure). [ atm, kPa, bar, psia, etc. ] | 1D3 |
pressure | atmospheric | 1D2 | |
pressure | gauge | Also known as Gage Pressure. The difference between the absolute pressure and atmospheric pressure. Gauge pressure is what is normally read from a pressure gauge. You must ADD atmospheric pressure to the gauge pressure to obtain the absolute pressure. Gauge pressures CAN be negative ! [ atm, kPa, bar, psig, etc. ] | 1D3 |
pressure | partial | For each species in a gas phase, it is the fraction of the total pressure that is caused by the presence of that species. If all of the other type of molecules were removed from the vessel, the final pressure would be the partial pressure of the remaining species. | 2D1 , 2 , 4 , 5 , 6 , 8 , 9 |
pressure | reduced | A dimensionless pressure used with the generalized compressibility charts and other EOS's. The Reduced Pressure, Pr, is defined as the ratio of the absolute pressure of the system to the critical pressure of the species in the system. As the reduce pressure approaches one, the pressure of the system approaches the critical pressure. | 2E9 |
pressure | vacuum | Pressures below atmospheric pressures. Vacuum Pressure equals atmospheric pressure minus the absolute pressure in the system. Vacuum pressures are only used when the system pressure is below atmospheric, so they generally only take positive values. For example, when the vacuum pressure is 10 kPa, the gauge pressure is - 10 kPa. | 1D3 |
pressure | vapor | The pressure that a pure liquid COULD overcome in order to boil. Vapor pressure depends on temperature only. If we keep the temperature constant and begin reducing the pressure starting from a very high pressure, then the vapor pressure at our fixed temperature is the pressure at which the liquid begins to boil (first bubble of vapor forms). [atm, Pa, bar,...] | 2B2 , 6, 2C2, 2D2 , 6 , 8 , 9 |
pressure gage | 1D7 | ||
pressure ratio | 9F5 , 6 | ||
pressure transducer | A sensor device that converts the pressure applied to its surface into an electrical signal. The pressure can be determined from the electrical signal. | 1D7 | |
principle of corresponding states | For all gases at the same reduced temperature and reduced pressure, many physical properties, including the compressibility factor, Z, are the same. | 2E8 | |
principle of increasing entropy | 7C6 , 7, 8A2, | ||
principle phases | The three principle phases are gas, liquid, and solid. | 2A4 | |
problem solving procedure | 4D1 - 10 | ||
process | A Process occurs in thermodynamics when any property of a system changes. | 1D1 , 3 , 4 | |
process | adiabatic | A process in which no heat transfer across the system boundary occurs. | 4B8 , 9, 4C3 - 5, 6F11 |
process | cyclic | ||
process | irreversible | 6D2 | |
process | isentropic | 7E1 - 7 | |
process | isobaric | A process during which the pressure remains constant. | 1D3, 4E1 - 3, |
process | isochoric | A process during which the volume of the system remains constant. | 1D3, 4E1 - 2 , 5, |
process | isothermal | A process during which the temperature remains constant. | 1D3, 4A17 - 18, 6F9 , 12 |
process | internally reversible | ||
process | path | 1D2 | |
process | polytropic | A process in which the volume and pressure of a system are related by an equation of the form: PV^n = C , where C and n are constants. | 4A17 , 19, 7A1, 7E7 |
process | reversible | 6D2, 7B2, | |
process | steady-state | A process in which properties may vary with posistion within the system, but none of the properties of the system change with time. | 5C5 |
process | transient | A process during which at least one property of the system changes as a function of time. This type of process is also known as an unsteady processes. | 5D1 |
process path | The actual series of states that the system passes through as it moves from the initial state to the final state during a process. | 3D1 - 4, 4A17, 4E1 | |
process path | hypothetical | 3D4 - 22, 3E1 , 4 - 9, | |
property | Also known as thermodynamic properties. Any characteristic of a system is a property of the system. Thermodynamic properties generally relate to the pressure, volume, temperature or energy of a system. | 1C4 | |
property | extensive | 1C4 , 5, 3C4, | |
property | intensive | 1C4 - 6, 3C4, 3D1 - 4 | |
property | molar | 1C4 | |
property | specific | 1C4 | |
pseudo-component | 2A2 | ||
psia | 1D2 | ||
psig | 1D2 | ||
PT diagram | 2B8 | ||
pump | 6B5, 6E17, | ||
pure substance | A pure substance has uniform chemical composition. This usually means that only one type of molecule is present. But a mixture such as air can be considered to be a pure substance as long as the composition of the air is the same throughout the system and none of the molecules that make up air (principally O2 and N2) participate in a chemical reaction. | 2A1 - 3, 2D1, | |
PV diagram | 2B6, 4A9 - 13, 7B11 | ||
PV diagram | area under a process curve | 7D3 | |
PV diagram | Carnot cycle | 6E3 - 23 | |
PV diagram | enclosed area | 7B14 | |
PV diagram | power cycle | 7B14 | |
PV work | 4A9, 5B6, | ||