Lecture 3 / PURE SUBSTANCES

Question 1

is
a substance that has
a fixed chemical
composition
throughout.
E.g. water, nitrogen,
helium, and carbon
dioxide

Answer 1

Pure substances

Question 2

_________ molecules are
arranged in a ______ which
is an ordered array of points
describing the arrangement
crystal-forming particles.

Answer 2

SOLID ; LATTICE

Question 3

_______ is a __________
state since it is not ready to
vaporize.

Answer 3

STATE 1 ; a compressed liquid

Question 4

It is called a __________
– a liquid that is about to
vaporize.

Answer 4

STATE 2 ; saturated liquid

Question 5

Once boiling starts, the
temperature stops rising until
the liquid is completely
vaporized.

That is, the temperature will
remain constant during the
entire phase-change process
if the pressure is held
constant.

Answer 5

STATE 3

Question 6

Any heat loss from this vapor
will cause some of the vapor
to condense (phase change
from vapor to liquid).

A vapor that is about to
condense is called a
____________

Answer 6

STATE 4 ; saturated vapor

Question 7

A vapor that is not about to
condense is called a
___________________
Therefore, water at ________ is
__________________

Answer 7

STATE 5 ; superheated vapor

Question 8

the amount of energy
absorbed or released during a
phase-change process

Answer 8

Latent heat

Question 9

the amount of
energy absorbed during melting equal to
the amount of energy released during
freezing

Answer 9

Latent Heat of Fusion

Question 10

the
amount of energy absorbed during
vaporization equal to the energy
released during condensation

Answer 10

Latent Heat of Vaporization

Question 11

the quantity of hfg is called

Answer 11

Latent Heat of Vaporization

Question 12

the point at which the saturated
liquid and saturated vapor states are identical

Answer 12

Critical Point

Question 13

The ____________ separates the solid and vapor
regions;

Answer 13

sublimation line

Question 14

The ________________ separates the liquid and vapor
regions;

Answer 14

vaporization line

Question 15

And the __________ line separates the solid and
liquid regions.

Answer 15

melting or fusion

Question 16

The
aforementioned
three lines meet
at the ___________, where all
three phases
coexist in
equilibrium.

Answer 16

triple
point,

Question 17

the temperature at which a
pure substance changes
phase at a given pressure

Answer 17

saturation temperature, Tsat

Question 18

the pressure at which a pure
substance changes phase at
a given temperature

Answer 18

saturation pressure, Psat

Question 19

A plot of Psat versus Tsat is
called a

Answer 19

liquid–vapor
saturation curve.

Question 20

All the states that
involve both phases
in equilibrium are
located under the
dome, called the

Answer 20

saturated
liquid–vapor mixture
region,

Question 21

A thermodynamic property
designed simplify our
reference to the combined
values of Pv and u terms.

Answer 21

Enthapy, h

Question 22

To analyze this mixture
properly, we need to know
the proportions of the liquid
and vapor phases in the
mixture.

This is done by defining a
new property

called the___________

Answer 22

quality x

Question 23

the ratio of the
mass of vapor to the total
mass of the mixture:

Answer 23

Quality, x

Question 24

Any equation that
relates the pressure,
temperature, and
specific volume of a
substance is called an ______________

Answer 24

equation of state

Question 25

The simplest and
best-known equation of
state for substances in
the gas phase is the

Answer 25

ideal-gas equation of
state.