Title: States of Matter
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4What is Energy?
5Energy The ability to do work and overcome
resistance.
Sounds a lot like force, but
6Name some forms of energy
7Name some forms of energy
- 1. Work
- 2. Thermal (heat)
- 3. Kinetic (energy of motion)
- 4. Potential (gravitational potential)
- 5. Electromagnetic
- (Electrostatic gt electrical potential)
- 6. Electromagnetic wave (gamma, x-ray, uv, light,
heat, micro, radio, etc.) - 7. Mechanical
- 8. Mechanical wave (sound, earthquake, )
- 9. Chemical potential
- 10. Nuclear
8What is Work?
9Work A force acting through a distance.W F
d
10Work A force acting through a distance.W P
?V
This is the work of a engine cylinder
11What is Pressure?
12Pressure Force per unit areaP F / A
alsoP ? g h? is density, g is Earths
gravity, and h is height of column of overlying
matter
-English unit is psi , SI unit is
Pascal -swimming pools and ears, car tires
(fluids) -Outland movie starring Sean Connery
Swords for 500 please Ah, thats S-words for
500, Mr. Connery -Total Recall movie starring
Ahnold
13Pressure as P ? g h? is density, g is Earths
gravity, and h is height of column of overlying
matter
Fun calculation for your enjoyment only -can also
express pressure in atmospheres, bars, and
various heights. 1 atm 760 mmHg
(13.5g/cm3)(9.8 m/s2)(.760m)(1000 kg/m3 /
g/cm3) 1x106 Pascals 14.7 psi 29.92
inchesHg 33 ft water 1 bar -an atmosphere
of pressure supports a water column 33 ft
high!! -Healthy blood pressure of 120 mmHg over
80 mmHg becomes 880 mmHg over 840 mmHg in outer
space!! -See Outland movie starring Sean Connery
for results Sean Connery Swords for 500
please Jeopardy host Ah, thats S-words for
500, Mr. Connery -or, see Total Recall movie for
results, starring Ahnold
14Energy has 3 laws called the Laws of
Themodynamics
- but before we can understand them, we must
define what is meant by heat and temperature of a
system. - What is a system?
15A system is a part of the universe separated out
for study.
- Open system exchanges energy and matter with
the surroundings. - Closed system exchanges energy, but not matter
(most common). - Isolated system does not exchange matter or
energy.
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17What is Temperature?
18Charles Law And Absolute Zero
19 Laws of Themodynamics
20Zeroth lawSystems at the same temperature have
the same internal energy0th. (Zeroth) If U
internal energy, U1 U2 if T1 T2Temperature
is thus a measure of the internal energy of a
system, starting at absolute zero, the convergent
point of Charles Law
211st law(Law of conservation of energy)Energy
is neither created nor destroyed, it just changes
form.
1st ?U Q W Q Heat W Work
222nd lawEnergy can only be changed in one
direction that is from usable to unusable, from
available to unavailable, or from ordered to
disorderedEntropy is the measure of the extent
to which available energy in any subsystem of the
universe is transformed into an unavailable form.
(The Rifken statement of the 2nd law, p.
46)2nd In extracting energy from a
reservoir, not all the energy can be converted to
work. Some of the energy, Qu, MUST be lost
(dissipated) as heat. Entropy is a measure of
this loss ?S Qu / T