Basic Principles, Concepts, and Definitions Flashcards
science of energy
Thermodynamics
Thermodynamics is derived from ________ meaning ________
Greek words therme (heat) & dynamis (power)
If you can measure something, it has a _______.
dimension
primary or fundamental dimensions
mass, length, time, temperature
secondary or derived dimensions
velocity, energy, volume
magnitudes assigned to the dimensions
units
can be used to quantify the size of a dimension
units
Two Different Unit of Systems
English System, Systeme Internationale (SI) or Metric or International System
unit system most common in the US
English system
Has no apparent systematic numerical base, and various units in this system are related to each other arbitrarily
English system
system used by everyone except the United States
Systeme Internationale (SI) or Metric or International System
Simple and logical system based on a decimal relationship between the various units
Systeme Internationale (SI) or Metric or International System
SI stands for
Systeme Internationale
defined as a quantity of matter or a region in space chosen for study
system
real or imaginary surface that separates the system from its surroundings
boundary
can also be fixed or moving and must be the contact surface both shared by the system and the surroundings
boundary
Types of Systems
open, closed, isolated
type of system where mass and energy to freely flow through the boundary
open system
type of system where energy can transfer between the system and the surrounding but not mass
closed system
type of system where neither mass nor energy can transfer between the system and the surroundings
isolated system
Properties of a System
intensive, extensive
properties that are independent of the mass of a system
intensive
properties whose values depend on the size or extent of the system
extensive
examples are temperature, pressure, density
intensive
examples are volume, mass, energy, momentum
extensive
law used in analyzing the flow of energy in a process or cycle
First Law
law used to analyze generation of entropy in a process or cycle
Second Law
states that when two objects are at the same temperature, they do not transfer heat
Zeroth Law
It says that if two bodies are independently in thermal equilibrium with a third body, they’re in thermal equilibrium with each other.
Zeroth Law
states that energy cannot be created or destroyed; it can only change form
First Law
First Law is also known as
Law of Conservation of Energy
Three Ways Energy can Leave a System
as form of work, form of heat, by adding or removing mass from the system
a collection of concepts about the quality of energy for performing a process
Second Law
High temperature reservoir is known as the ________, and
the low-temperature reservoir is known as the ________.
heat source, heat sink
provides the basis for determining the maximum theoretical limit for efficiency of a cycle
Second Law
realistic behaviors that generate entropy
temperature difference, friction
essence is the concept of zero entropy at zero temperature
Third Law
property in thermodynamics that describes the amount of material used in a system or process
mass
force exerted on an object by gravity
weight
defined as mass per unit volume
density
reciprocal of density
specific volume
defined as volume per unit mass
specific volume
defined as the ratio of a density of a substance to the density of some standard substance at a specified temperature
specific gravity or relative density
other term for specific gravity
relative density
dimensionless constant
specific gravity
weight of a unit volume of a substance
specific weight
defined as a normal force exerted by a fluid per unit area
pressure
Types of Pressure
absolute, gage, vacuum
Actual pressure at a given position and is measured relative to absolute volume
absolute pressure
difference between the absolute pressure and the local atmospheric pressure
gage pressure
pressures below the atmospheric pressure
vacuum pressure
Measure by vacuum gages which indicates the difference between the atmospheric pressure and the absolute pressure
vacuum pressure
Commonly used to measure small and moderate pressure differences
manometer
Mainly consists of a glass or plastic U-Tube containing one or more fluids such as mercury, water, alcohol or oil
manometer
measures atmospheric pressure
barometer
describes how hot or cold something is; concept used to describe the direction in which heat transfer takes place
temperature
form of energy that naturally flows from hot to cold temperatures
heat
developed Celsius
Anders Celsius
proponent of Fahrenheit
Daniel Gabriel Fahrenheit
proponent of Kelvin
1st Baron Kelvin of Largs
proponent of Rankine
William Rankine
Principle of Conservation of Mass
Mass can be neither created nor destroyed
