ABSTRACT

Firstly, the aim of this experiment is to determine the properties of measurement/PVT.

While, the equipment that’s had been used is called Perfect Gas Expansion. All four

experiments were conducted successfully. In the first experiment that we conducted to

show the Boyle’s Law and to determine the ratio of volume. In our experiment, the

experiment is repeated for three times from pressurized chamber to vacuum chamber,

from atmospheric chamber to pressurized chamber and increase the gas of both

chamber and let it merge by opening the valve no 2,V02. Next, the second experiment

is to determine the Gay-Lussac Law and it also done repeatedly for three times to get

the average value of the temperature at pressurize and depressurize vessels.

Moreover, after getting the average value, the graph of pressure versus temperature is

plotted. Then in the third experiment, is to conduct the isentropic expansion process.

When conducted this experiment, the pressure and the temperature of pressurized

chamber is taken before and after the expansion occur. Lastly, the fourth we need to

determine the ratio of heat capacity. When we conducted the experiment only the

pressurized chamber and compressive pump are used during this experiment. We can

concluded that, based on all the experiments that we conducted, all the data which are

about the reading before and after the setting are recorded into the data as below.

RECOMMENDATION

For the improving the system of properties of measurement /PVT , it is recommended

that the properties of measurement /PVT have their own alert sign system that can give

a sign to the engineer who handles the equipment to take the readings at the correct

and accurate time in order to get accurate readings. So, this can help in reducing the in

accuracy of the measurements. There are many recommendations when operating the

heat exchanger experiment are as follows:

Safety glasses with side shields shall be worn at all times during the experiment.

Prior to operation of the system, familiarize yourself with the equipment. Trace

all process lines, test all valves, and ensure that all valves are closed.

Open and close the switch of the instrument safely.

Keep the laboratory working space clean and uncluttered

There is no waste associated with this experiment.

Each experiment we must do the start-up and shut-down experiment first in

order to make sure there are no gas are left in the chamber.

We must ovoid the parallax error during taking the reading of pressure and

temperature.

Repeat the experiment three time to get the average and more accurate result.

Open and close the valve carefully according to the procedure given.

The experiment should be conducted at the stable and unshaken place.

All the data must be recorded into a table.

Tighten the hose before pumping

THEORY

 Boyle’s law experiment and determination of volume ratio

 Boyle's Law states that the product of the pressure and volume for a gas is a constant

for a fixed amount of gas at a fixed temperature. Written in mathematical terms, this law

is

P x V = constant

 A common use for this law is to predict on how a change in pressure will alter the

volume of gas or vice versa. Therefore, for initial values of P1 and V1, which change to

final values of P2and V2, the following equation applies

P1x V1= P2 x V2 (for fixed amount of gas at constant temperature)

The graph shows how the pressure and volume vary according to Boyles Law at two

difference temperatures. Then it can be conclude that, the pressure and volume gas is

indirectly related which is if the pressure of the chamber is increase then the volume of

the gas inside the chamber also decrease. Besides, it also involves the kinetic energy. If

we decrease the volume of a gas, thus means that the same number of gas particles

are now going to come in contact with each other and with the sides of the container

much more often. The pressure is also measure the frequency of collision of gas

particle with each other and with the side of the container they are in. Thus if the volume

decrease, the pressure will naturally increase. The opposite is true if the volume of the

gas is increased, the gas particles collide less frequently and the pressure will

decrease.

At lower temperatures the volume and pressure values are lower. Any volume or

pressure units can be used as long as both P's and both V's have the same units. The

particle theory and simple arithmetical values are used to explain Boyles Law.

When the volume of gas is compress into half, the collision of the gas will

increase and thus the pressure will increase double compare to the origin value.

But if the volume of the gas is doubled or increase in the factor of two, the

collision drop and decrease thus the pressure will decrease into half compare to

the origin.

Gay-Lussac Law theory

Compare to the Boyle’s Law, the expression of Gay-Lussac’s Law is used for each of

the two relationship named after the French chemist Joseph Louis Gay-Lussac (1778-

1850)and which concern the properties of gases, though it is more usually applied to his

law of combining volumes. One law relates to volumes before and after chemical

reaction while the other concerns the pressure and temperature relationship for a

sample of gas. According to Gay-Lussac’s law, for a given amount of gas held at

constant volume, the pressure is proportional to the absolute temperature.

Mathematically,

P α T or P = kGT = P/T = kG

Where, kG is the appropriate proportionality constant.

Besides, Gay-Lussac ‘s law also tells us that it may be dangerous to heat a gas in a

closed container. The increased pressure might cause the container to explode.

Therefore, for initial values of P1and T1, which change to final values of P2 and T2 , the

following equation applies

P1 / T1 = P2 / T2 or P1V1 = P2V2

In all calculations, the absolute or Kelvin scale of temperature must be used for

T (K = oC +273).

Based on Gay-Lussac it stated that the pressure exerted on a container’s sides by an

ideal is proportional to the absolute temperature of the gas. This follows from the kinetic

theory which stated that by increasing the temperature of the gas, the molecules ‘speed

increase meaning an increased amount of collisions with the container walls.

Determination of ratio of heat capacity theory

For a perfect gas,

Cp = Cv + R

Where,

Cp = molar heat capacity at constant pressure, and

Cv = molar heat capacity at constant volume.

 For a real gas a relationship may be defined between the heat capacity, which is

dependent the equation of state, although it is more complex than that for a perfect gas.

The heat capacity ratio may then be determined experimentally using a two steps

process.

An adiabatic reversible expansion from the initial pressure Ps to an intermediate

pressure Pi

{Ps, Vs, Ts} {Pi, Vi, Ti}

A return of the temperature to its original value Tsat constant volume Vi

{Pi, Vi, Ti} {Pf, Vi, Ts}

For a reversible adiabatic expression

dq = 0

From the First Law of Thermodynamics,

dU = dq + dW

Therefore during the expansion process

dU = dW or dU = -pdV

At constant volume the heat capacity relates the change in temperature to the

change in internal energy

dU = CvdT

Substituting in to equation x,

CvdT = -pdV

Substituting in the ideal gas law and then integrating gives

CV In ( Ti /Ts) = -R In ( Vi / Vs )

Now, for an ideal gas

Ti / Ts = PiVi / PsVs

Therefore,

CV ( In Pi / Ps + In Vi / Vs ) = -R In Vi / Vs

Rearranging and substituting in from equation x,

In Pi / Ps = (-CP / CV ) In Vi / Vs

During the return of the temperature to the starting value,

Vi / Vs = Ps / Pf

Thus,

In ( Ps / Pf ) = ( CP / CV ) In ( Ps / Pf )

Rearranging gives the relationship in its required form:

CP / CV = ( In Ps - In Pi ) / (In Ps - In Pf )

Isentropic expansion process theory

 In thermodynamics, an isentropic process or can be called isoentropic process is a

process takes place from initiation to completion without an increase or decrease in the

entropy of the system. The entropy of the system remains in constant. Entropy is a type

of energy (like heat, work, and enthalpy) and is by definition energy which is lost in a

process which is characterized by:

ΔS = 0 or S1= S2

If a process is both reversible and adiabatic, then it is an isentropic process. An

isentropic process is an idealization of an actual process, and serves as a limiting case

for an actual process. For adiabatic, there is no transfer of heat energy

APPARATUS

Figure 1: Perfect gas expansion apparatus, model TH 11

1. Pressure Transmitter2. Pressure Relief Valve3. Temperature Sensor4. Big glass5. Small glass6. Vacuum pump7. Electrode

INTRODUCTION

The Perfect Gas Expansion Apparatus comes with one pressure vessel and one

vacuum vessel .Both vessels are made from glass. The vessels are interconnected with

two sets of piping and valve set allows fast charge and a small diameter pipe and

needle valve set provides gradual charge. Vacuum pressure air pump is provided to

pressurize or evacuate air inside the vessels with the valves configured appropriately.

The pressure and temperature sensors and clearly displayed by digital indicator on the

control panel. With an optional automatic data acquisition system, the modern version of

classic Clement and Desormes experiment can be conducted as pressure and

temperature changes can be monitored continuously with the PC. Experiment of

measurement properties or PVT deals with ideal gas. An ideal gas is a gas that obeys

the relationship PV=RT. In this definition P and T are the absolute pressure and

absolute temperature respectively and R is the particular gas constant. The particular

gas constant depends on the molecular weight of the gas. The perfect gas expansion

which allow students familiarize with several fundamental thermodynamic processes

can be manipulate by monitored the digital indicator on the control panel. Therefore, this

apparatus should not harm students. However, students should take care about their

safety during the experiment. The most important thing that student should do is open

the valve slowly when releasing the gas inside the vessel to atmosphere because there

are high pressure gas inside the vessel that being released by the valve that can be

harm to students. Gas particles in a box collide with its walls and transfer momentum to

them during each collision. The gas pressure is equal to the momentum delivered to a

unit area of a wall, during a unit time. Ideal gas particles do not collide with each other

but only with the walls .A single particle moves arbitrarily along some direction until it

strikes a wall. It then bounces back, changes direction and speed and moves towards

another wall. The gas expansion equations are derived directly from the law of

conservation of linear momentum and the law of conservation of energy.

CONCLUSION

Based on the experiment that we conduct , we can concluded that the experiment was

to determining the properties measurement/PVT according to Boyle’s Law, Gay-Lussac

Law, heat capacity equation and isentropic expansion process. Sometimes when we

conducted this experiment we make some parallax error but we still manage to get the

result of what we want such as in experiment one which me manage to prove the

Boyle’s law that is when pressure decrease the volume will increase and vice versa. On

top of that, we also manage to prove the Gay-Lussac law that is pressure is proportional

to temperature. In conclusion, this experiment is successfully done and the objective of

the experiment is achieved.

REFERENCES

Yusus A. Cengel, M. A. (2011). second low of thermodynamics.Thermodynamics

an engineering apploach (pp. 274-309). New York: Mc Graw Hill.

Hutchinson, John. The Ideal Gas Law. Connexions. 16 Jan. 2005

<http://cnx.org/content/m12598/1.2/>.

Laugier, Alexander; Garai, Jozef. "Derivation of the Ideal Gas Law." Journal of

Chemical Education. 2007, Vol. 84, Iss. 11, pgs. 1832 -1833.

Draper, John William (1861). A Textbook on chemistry. p. 46.

Jump up ^ Levine, Ira. N (1978). "Physical Chemistry" University of Brooklyn:

McGraw-Hill.

AIMS

To determine the ratio and compares it to the theoretical value.

To determine the ratio of heat capacity.

To determine the relationship between pressure and volume of an ideal gas law

To compare the experiment result with theoretical result.

To determine the relationship between pressure and temperature of an ideal gas.

To demonstrate the isentropic expansion process.

To study the respond of the pressurize vessel following stepwise

depressurization.

To study the response of the pressurized vessel following a brief

depressurization.

RESULTS

EXPERIMENT 1: Boyle’s Law Experiment & Determination of Ratio Volume

TABLE1: From pressurized chamber to atmospheric chamber

Before expansion After expansionPT 1 (Kpa abs.) 152.0 145.9PT 2 (Kpa abs.) 134.9 145.2

TABLE2: From atmospheric chamber to vacuum chamber

Before expansion After expansionPT 1 (Kpa abs.) 108.0 91.2PT 2 (Kpa abs.) 58.8 90.8

TABLE3: From pressurized chamber to vacuum chamber

Before expansion After expansionPT 1 (Kpa abs.) 153.5 121.4PT 2 (Kpa abs.) 58.8 121.6

EXPERIMENT 2 :Gay-Lussac Law Experiment

TRIAL 1 TRIAL 2 TRIAL 3PRESSURE(Kpa abs.)

TEMPERATURE (ºC) TEMPERATURE (ºC) TEMPERATURE (ºC)

Pressure rise

vessel

Depressure rise vessel

Pressure rise

vessel

Depressure rise vessel

Pressure rise

vessel

Depressure rise vessel

110 22.6 22.3 22.1 22.6 22.2 23.1120 22.9 22.8 22.3 23.3 22.4 24.1130 23.5 23.6 22.8 24.5 23.0 25.3140 24.5 24.8 23.9 25.7 23.8 26.6150 25.4 26.6 24.8 26.8 24.8 26.9160 26.3 27.9 25.9 27.3 25.6 27.0

EXPERIMENT 3 : Determination of Ratio of Heat Capacity

INITIAL INTERMIDIATE FINALPT 1 (Kpa abs.) 160.0 138.2 141.6TT1 ( ºC) 26.7 26.2 24.4

EXPERIMENT 4 :Isentropic Expansion Process

Before expansion After expansionPT 1 (Kpa abs.) 163.0 103.5TT1 ( ºC) 25.2 21.7

PROCEDURES

4.1 General Operating Procedures

4.1.1 General Start-up Procedures

1. The equipment is connected to power supply and the unit is switched on

2. All the valves are fully opened and the pressure reading on the panel are checked.

3. Then, all the valves are closed.

4. Pipe from compressive port of the pump is connected to pressurize chamber or pipe

from vacuum port of the pump is connected to vacuum chamber .( depends on

experiment)

4.1.2 General Shut-down procedures

1. The pump is switched off and the both pipes are removed from the chambers.

2. The valves are fully opened and the main switch and power supply is switched off.

4.2 Experiment 1 : Boyle’s Law Experiment &Determination of Ratio Volume

1. The general start up is performed.

2. The compressive pump is switched on and the pressure inside the chamber

increased up until 150.7kPa. The pump is switched off and the hose is removed.

3. The pressure reading for both chambers before expansion is recorded

4. The V02 is fully opened and pressurized air is allowed to flow to the atmospheric

chamber.

5. The reading for both chambers after expansion is recorded

6. This procedure is repeated in following condition:

a) from atmospheric chamber to vacuum chamber

b) from pressurize chamber to vacuum chamber

7. The PV value is calculated and the Boyle’s law is proved

8. The ratio volume is calculated and it is compared with theoretical value.

4.3 Experiment 2 :Gay-Lussac Law Experiment

1. The general start up is performed.

2. Hose from compressive pump is connected to pressurized chamber.

3. The compressive pump is switched on and for every increment of 10kPa,the

temperature is recorded, starting from 101.6kPa. The pump is stopped at PT1 showed

161.7kPa.

4. Then, the V 01 is slightly opened the pressurized air is allowed to flow out. The

temperature reading for every decrement of 10kPa is recorded starting at 151.7kPa.

5. When the pressure reached the atmospheric pressure, the experiment is stopped.

6. The graph of pressure versus temperature is plotted.

4.4 Experiment 3 : Determination of Ratio of Heat Capacity

1. The general start up is performed.

2. Hose from compressive pump is connected to pressurized chamber.

3 .The compressive pump is switched on and the pressure is increased up until

154.4kPa. Then, the pump is switched off and the hose is removed.

4. The pressure reading is monitored until it is stabilized. The pressure and temperature

reading, PT1 and TT1 are recorded.

5. The V01 is slightly opened and closed back after 3 seconds. The pressure and

temperature reading is monitored and recorded

6. Ratio of heat capacity is determined and it is compared with theoretical value.

4.5 Experiment 4 :Isentropic Expansion Process

1. The general start up is performed.

2. Hose from compressive pump is connected to pressurized chamber.

3. The compressive pump is switched on and the pressure is increased up until

157.6kPa. then, the pump is switched off and the hose is removed.

4. The pressure reading is monitored until it is stabilized. The pressure and temperature

reading, PT1 and TT1 are recorded.

5. The V01 is slightly opened and the air is allowed to out until reaching atmospheric

pressure.

6. The pressure and temperature reading is and recorded.

7. The isentropic expansion process is discussed.