Chapter 19 Flashcards
Two objects
that are separately in thermal equilibrium with
a third object are in thermal equilibrium with
each other.
Zeroth law of thermodynamics
Two objects are defined to have the same
temperature if they are
in thermal equilibrium
with each other
5/9 (T in F - 32)
T in C
9/5 (T in C + 32)
T in F
If you plot a graph with Fahrenheit temperatures
along the horizontal axis and the corresponding
Celsius temperatures along the vertical axis, the
slope of the equal-temperature line will be
0.56 C/F
Rankine (R)
F + 459.67
As temperature increases, the amplitude
increases, causing the overall
object as a whole to expand.
When the
temperature changes by T, the fractional change in length L is
proportional to T. is called the coefficient of linear expansion.
Alpha units
C^-1 and K^-1
a nickel steel
alloy notable for its uniquely low
coefficient of thermal expansion
Invar
coefficient of areal expansion
Y
coefficient of volume expansion
B
A sheet of metal has a star shaped hole.
What happens to the distance, d, when the
temperature of the sheet is increased?
Increases
consists of two pieces of metal,
with different coefficients of expansion, bonded to
each other.
Bimetallic Strips
used to convert a temperature change into
mechanical displacement
Bimetallic Strips
Used to increase the magnitude of the displacement in a confined space
Bimetallic Strip Coils
As the temperature of water increases from 0ºC to 4 ºC, it
contracts and its density increases
Above 4 ºC, water exhibits
the expected expansion with
increasing temperature
The maximum density of water is
1000 kg/m3 at 4 ºC
How much water spills out of the flask?
Both Volume expansion formulas
At what temperature will the bar break?
Y = (F/a) / (dLf / L)
Properties of Gases
- No fixed volume or pressure
2. Expands to fill the container
Collection of atoms or molecules that move randomly
– Molecules exert no long-range force on one another
– Molecules occupy a negligible fraction of the volume of their
container
Ideal Gas
NA =
6.022 X 10^23 atoms
Mass of Atom
Molar mass / NA
PV = Constant
Boyles
V/T = Constant
Charles
P/T = Constant
Gay-Lussac
An ideal gas is confined to a container with constant volume.
The number of moles is constant. By what factor will the
pressure change if the absolute temperature triples?
3
An ideal gas is confined to a container with adjustable volume.
The number of moles and temperature are constant. By what
factor will the volume change if pressure triples?
1/3
A mass of He gas occupies a volume V at
standard temperature and pressure. What volume
is occupied if the mass is halved, the absolute
temperature doubled, and the pressure increased
by a third?
(3/4)V
another quantity commonly determined for gas
mixtures. It is defined the number of moles of one substance
relative to the total number of moles in the mixture
Mole Fraction
The sum of the partial pressures of the gases in a
mixture = the total pressure, or P = PA + PB + PC + … Pi
where Pi = the partial pressure of component i.
Dalton’s Law
