Question | Answer |
Absolute Pressure | the actual pressure at a given position and it is measured relative to absolute vacuum. |
Barometer | is a device that measures the atmospheric pressure |
Boundary | is the real or imaginary surface that separates the system from its surroundings. The boundary of a system can be fixed or movable. |
Calorie | is the amount of energy in the metric system needed to raise the temperature of 1 g of water at 15 °C by 1°C. |
Closed System | consists of a fixed amount of mass, and no mass can cross its boundary. But energy, in the form of heat or work, can cross the boundary. |
Control Volume | is any arbitrary region in space through which mass and energy can pass across the boundary. Most control volumes have fixed boundaries and thus do not involve any moving boundaries. |
Cycle | is a process, or series of processes, that allows a system to undergo state changes and returns the system to the initial state at the end of the process. |
Extensive Properties | are those whose values depend on the size-or extent-of the system. Mass m, volume V, and total energy E are some examples of extensive properties. |
Gage Pressure | is the difference between the absolute pressure and the local atmospheric pressure. |
Heat Transfer | is defined as the form of energy that is transferred between two systems (or a system and its surroundings) by virtue of a temperature difference. |
Intensive Property | are those that are independent of the size of a system, such as temperature, pressure, and density. |
Isolated System | is a closed system in which energy is not allowed to cross the boundary. |
Joule | is a unit of energy and has the unit "newton-meter (N·m)." |
Manometer | is a device based on the principle that an elevation change of Δz of a fluid corresponds to a pressure change of ΔP/ ρg, which suggests that a fluid column can be used to measure pressure differences. |
Newton | in SI, is the force unit defined as the force required to accelerate a mass of 1 kg at a rate of 1 m/s2. |
Open System | is any arbitrary region in space through which mass and energy can pass across the boundary. |
Phase Equilibrium | when a system involves two phases is established when the mass of each phase reaches an equilibrium level and stays there. |
Process | is any change that a system undergoes from one equilibrium state to another. To describe a process completely, one should specify the initial and final states of the process, as well as the path it follows, and the interactions with the surroundings. |
Property | is any characteristic of a system. Some familiar properties are pressure P, temperature T, volume V, and mass m. |
Second Law of Thermodynamics | asserts that energy has quality as well as quantity, and actual processes occur in the direction of decreasing quality of energy. |
State | is the condition of a system not undergoing any change gives a set of properties that completely describes the condition of that system. At this point, all the properties can be measured or calculated throughout the entire system. |
State Postulate | specifies the number of properties required to fix the state of a system: The state of a simple compressible system is completely specified by two independent, intensive properties. |
Steady-Flow Process | is defined as a process during which a fluid flows through a control volume steadily. That is, the fluid properties can change from point to point within the control volume, but at any fixed point they remain the same during the entire process. |
Vacuum Pressure | is the pressure below atmospheric pressure and is measured by a vacuum gage that indicates the difference between the atmospheric pressure and the absolute pressure. |
Zeroth Law of Thermodynamics | states that if two bodies are in thermal equilibrium with a third body, they are also in thermal equilibrium with each other. |
Deg F | 9/5*Dec C + 32 |
Deg C | ( Deg F -32 )*5/9 |
P gage = | P abs - P atm |
P vac = | P atm - P abs |