key terms pt.2 Flashcards
work
force through a distance
Mass density
Mass/Unit Volume
Intensive Properties
properties which are independent of the size of the system (2 extensive = intensive) - SPECIFIC - NOT UNDERLINED
Extensive Properties
properties which depend on the size/amount of/in the system (volume and energy) - UNDERLINED
State Variables
intensive properties that specify/define the state of the system. (T,P)
Gibb’s Phase Rule
F = C - P + 2
(F = DoF, C=#components, P=#phases)
Steady State (Open System)
mass flow into and out of the system but there is no accumulation
- State variables in a steady state system are invariant with time
Ideal Gas Law
PV_ = nRT
Specific Notation
UNDERLINE = NOT SPECIFIC, NOT PER MASS
Pressure
Force/Area (N/m^2)
Isothermal
At constant temperature
Critical Temperature
maximum temperature at which a fluid may exist as a liquid, temperature where vapor and pressure phases are identical - above this temperature = supercritical
Saturation Conditions
where 2 phases coexist - can refer to either bubble or dew conditions
Bubble Line
where boiling can occur
Dew Line
where droplets can occur in vapor
Critical Point
vapor and liquid phases are identical
critical pressure
pressure where vapor and liquid phases are identical
Superheated
vapor above its saturation temperature at a given pressure (above sat. temperature at system pressure)
USE SUPERHEATED TABLE when above saturation temp at a given pressure
Linear Interpolation Formula
y = y1 + (( x - x1 )/( x2 - x1)) ( y2 - y1 )
What must happen in order to use linear interpolation?
something must be constant!!
What is true of U and H for ideal gases?
They are only a function of temperature!!
Cv (heat capacity)
proportionality constant between temperature and INTERNAL ENERGY at a constant volume
ideal gas heat capacity and specific heat relation
Cp = Cv + R
isotherms
lines of constant temperature
phase envelope
hump on fig 1.4, two phases coexist when system conditions are inside or on the envelope
tie lines
horizontal lines inside the curves that show saturated liquid and saturated vapor volumes can coexist
describe what happens to an isotherm in figure 1.4
1)from the right the isotherm starts in the vapor region and decreases in volume as it moves left.
2) The pressure rises as the vapor is isothermally compressed. 3) the volume reaches the saturation curve at the vapor pressure and the liquid phase begins.
saturated steam
vapor at the dew point
steam
vapor state of water
Cp (heat capacity
proportionality constant between temperature and ENTHALPY at a constant pressure
STATE VARIABLES
P, U, T, V
