introduction for fundamentals english

8/13/2019 Introduction for fundamentals english

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Thermodynamic

M o h d A d l i B i n J a a f f a r

5 6 2 6 7 1 1 3 0 9 0

L 0 2 / T 0 1

0 1 3 - 6 4 5 5 5 2 0

1 2 / 8 / 2 0 1 3

LGB 31503

Report Of determine the

potential and kinetic

energy of a system


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1.0 Introduction

In the previous lesson regarding the Thermodynamic Law. There are a interesting part

where the chapter mention about energy. Based on my observation the law of thermodynamic are

correlate with the Principle of potential and kinetic energy. In this Report , Ill try my best toexplain the theory with some simple experiment that may give a glimpse upon this matter .

The laws of thermodynamics drive everything that happens in the universe. From the

sudden expansion of a cloud of gas to the cooling of hot metal everything is moved or restrained

by four simple laws. Based on the introduction regarding written by Peter Atkins, one of the

world's leading authorities on thermodynamics, this powerful and compact introduction explains

what these four laws are and how they work, using accessible language and virtually no

mathematics. Guiding the reader a step at a time, Atkins begins with Zeroth (so named because

the first two laws were well established before scientists realized that a third law, relating to

temperature, should precede them--hence the jocular name zeroth), and proceeds through theFirst, Second, and Third Laws, offering a clear account of concepts such as the availability of

work and the conservation of energy. Atkins ranges from the fascinating theory of entropy

(revealing how its unstoppable rise constitutes the engine of the universe), through the concept of

free energy, and to the brink, and then beyond the brink, of absolute zero1.

The field of thermodynamics deals with systems that are able to transfer thermal energy

into at least one other form of energy (mechanical, electrical, etc.) or into work. The laws of

thermodynamics were developed over the years as some of the most fundamental rules which are

followed when a thermodynamic system goes through some sort of energy change. The laws of

thermodynamics tend to be fairly easy to state and understand ... so much so that it's easy tounderestimate the impact they have. Among other things, they put constraints on how energy can

be used in the universe. It would be very hard to over-emphasize how significant this concept is.

The consequences of the laws of thermodynamics touch on almost every aspect of scientific

inquiry in some way2.

The laws of thermodynamics do not particularly concern themselves with the specific

how and why of heat transfer, which makes sense for laws that were formulated before atomic

theory was fully adopted. They deal with the sum total of energy and heat transitions within a

system, and do not take into account the specific nature of heat transference on the atomic or

molecular level.

1http://www.amazon.com/The-Laws-Thermodynamics-Short-Introduction/dp/0199572194

2http://physics.about.com/od/thermodynamics/a/lawthermo.htm


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2.0 The Four Law Of Thermodynamic

0th

Law of Thermodynamic (Zeroth Law)3

There is a state function, called temperature which has the symbol T, which has the following

relationship to heat, q:

addition of heat to a system will increase the temperature of the system.

if two closed system (together isolated), with different temperatures are brought into

thermal contact, then the temperatures of the two systems will change to approach the

same temperature. That is, the temperature of the system which is at a higher

temperature will decrease and the temperature of the system with the lower temperature

will increase. They will eventually have the same temperature.

The zeroth law leads to the general idea of heat capacity. The symbols Cp and Cv are used for

this (constant pressure and constant volume) but for solid there is usually little difference

between these two. Using the relationship at constant volume (and therefore Cv ) between a

change in temperature, T , of a substance and the amount of heat transferred, q, to this

substance is given by:

If one uses the concept of a molar heat capacity, Cv or Cp , where the bolding indicates a per

mole quantitiy, then for a simple compound one may write:

1stLaw Of Thermodynamic

4

There is a state function, the internal energy E (in some texts U), which has the following

properties:

in an isolated system E remains constant

addition of work, symbol w, to a closed system will increase the internal energy by the

amount of work expended.

3http://www.genchem.net/thermo/zerothlaw.html

4http://www.genchem.net/thermo/firstlaw.html

q = Cv T

At constant pressure:

q = Cp T

q = n Cv T

or

q = n Cp T


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For those who have calculus in your future, an increment of entropy designated by dS is related

to a small increment of added heat, q , by: dS = q /T

where dS is now an exact differential, but q is not. Thus 1/T is the integrating factor.]

If there is no net change in the state inside the isolated system then S = 0. This then is thethermodynamic criterion for equilibrium .Inside an isolated system, in order for a process to

proceed, S > 0. Such a process is said to be spontaneous. A process for which S < 0 is called

non-spontaneous and is impossible for an isolated system.

3rd

Law Of Thermodynamic6

The Third Law of Thermodynamics

Summary: As T 0 K , S 0.

The important point about the third law is that entropy is an absolute quantity which depends

upon temperature. This is in contrast to H for reactions which have as a reference the

elemental state.

Thus, when one looks up the H of of an elements, the answer is 0. In contrast, So for an

element (note difference in symbols as well) has a value for temperature above 0 K. Careful

when doing calculations for So of reactions that you do not use 0 for the So of the elements.

The entropy change with respect to temperature can be thought of a continuous summation of all

the increments of heat added to the system divided by the temperature at the time of the addition.

Or symbolically:

S = integral (dq/T) dT which is approximately SUM of the ( q /T) s

Thus, to calculate a change in S one simply adds up the little increments of heat added divided

by temperature.

The question then is, what if the addition of these increments start with the temperature at 0 K?

The answer is, that at 0 K the q added is also 0. 0 divided by 0 presents a dilemma and the third

law answers this by the following:

For a pure component in the most stable condition, S = 0 at T = 0 K. This leads to the

assumption needed above, that the So s for pure components are absolute values and are notreferenced against some arbitrary initial condition like the H o s are. As an illustration, see the

example thermodynamic table and notice that the elements do have Sos listed.

6http://www.genchem.net/thermo/thirdlaw.html


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3.0 Description of Experiment

Before i start detailing the report upon the experiment that i conduct to determine the potential

and kinetic energy of a system, I would like to explain a little bit the potential and kinetic energy

concept in thermodynamics as it is differ in other science field.

Potential energy, as the name implies, is energy that has not yet been used, thus the term

potential. Kinetic energy is energy in use (or motion). A tank of gasoline has a certain potential

energy that is converted into kinetic energy by the engine. When the potential is used up, you're

outta gas! Batteries, when new or recharged, have a certain potential. When placed into a tape

recorder and played at loud volume (the only settings for such things), the potential in the

batteries is transformed into kinetic energy to drive the speakers. When the potential energy is all

used up, the batteries are dead. In the case of rechargeable batteries, their potential is reelevated

or restored.

In the hydrologic cycle, the sun is the ultimate source of energy, evaporating water (in afashion raising it's potential above water in the ocean). When the water falls as rain (or snow) it

begins to run downhill toward sea-level. As the water get closer to sea-level, it's potential energy

is decreased. Without the sun, the water would eventually still reach sea-level, but never be

evaporated to recharge the cycle.

Chemicals may also be considered from a potential energy or kinetic energy standpoint.

One pound of sugar has a certain potential energy. If that pound of sugar is burned the energy is

released all at once. The energy released is kinetic energy (heat). So much is released that

organisms would burn up if all the energy was released at once. Organisms must release the

energy a little bit at a time. Energy is defined as the ability to do work. Cells convert potentialenergy, usually in the form of C-C covalent bonds or ATP molecules, into kinetic energy to

accomplish cell division, growth, biosynthesis, and active transport, among other things.7

In order to determine the potential and kinetic energy of a system I search the web to find

out about a simple experiment to be conduct to prove the 1stlaw of thermodynamics involving

kinetic and potential energy. Result by doing so, I found about a video about the changes of

energy by friction energy, that is the conversion of energy from kinetic to heat energy. When I

continue making research about it. I found out about something interesting. Next is my full

report regarding the task determining the potential and Kinetic energy is system.

7http://www2.estrellamountain.edu/faculty/farabee/biobk/biobookener1.html#Thermodynamics


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Report:

Experiment: Potential & Kinetic energy To Heat

First Law of Thermodynamics: Heating Sand by Shaking It:

The first law of thermodynamics says that the total amount of energy in a closed system remains

constant. There are many different forms of energy, and energy can shift from one form to

another. So the total amount of energy in a closed system is the sum of all the different forms of

energy added together.8

To test this principle, i measured the temperature of sand in a Styrofoam cup. This experiment

was suggested by Professor Robert Hazen in his video course The Joy of Science. In his video,

he used a jar of sand. However, i decided to use insulated cups so i didn't have to open it to

measure the heat. i first measured the sand's temperature, then i sealed the cup, shook it for about

five minutes, and measured the sand again. The sand's temperature actually changed from 65

degrees Fahrenheit to 68 in just the five or so minutes i shook it.

8http://en.wikipedia.org/wiki/Laws_of_thermodynamics

Materials:

2 disposable insulated cups (i used Styrofoam)

masking tape

sand

and a food thermometer (the kind with a sharp metal probe.)

Procedure:

Pour the sand into one of the cups until it is about three-

quarters full.

Measure the temperature of the sand.

Place the empty cup on top of the cup with the sand on it. Tape

them together.

Shake for five minutes.

Poke the thermometer's probe though the top of one of the

cups. Measure the temperature again.

The temperature go up a few degrees.

Material Setup


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Result And Discussion:

As previously explain like the cell(battery) the cell contain its own potential energy but

need another medium to convert it to another form of energy that is kinetic energy. Same goes as

to the sand. The sand have its own potential energy but the potential energy only occur when we

shaking the sand. By shaking the sand is a form of kinetic energy. The friction of the sandparticles rubbing against each other converts the kinetic energy to heat energy. Some of the

kinetic energy also converts into the energy of sound waves, which you can hear while you shake

the sand.

Conclusion:

It can be concluded that the kinetic and potential energy are correlate to each other. Potential

energy is the stored energy of position possessed by an object.An object can store energy as the

result of its position or object characteristic. So in this case, the sand store its potential energy to

produce heat. But to do so, it need a medium to change it to kinetic energy that is by shaking it.

After being shacked the sand unleashed heat as a result of the involvement of kinetic and

potential energy.

Sand ShakingHeat

Contain PotentialEnergy

Kinetic Energy areinvolve

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