result discussion lab 5 thermo

7/24/2019 Result Discussion Lab 5 Thermo

1/13

APPARATUS AND EQUIPMENT:

Perfect gas expansion apparatus, mode T! ""


2/13

PR#$EDURES:

%enera start&up

"' T(e e)uipments are connected to singe p(ase po*er supp+ and t(e unit is s*itc( on'

' T(en, open a -a-es and t(e pressure reading pane' T(is is to ma.e sure t(at t(e

c(am/ers are under atmosp(eric pressure'

0' After t(at, cose a t(e -a-es'

1' Next, connect t(e pipe from compressi-e port of t(e pump to pressure c(am/er or

connect t(e pipe from -acuum port of t(e pump to -acuum c(am/er' T(e connect must

not does at t(e same time'

2' No*, t(e unit is read+ to use'

Experiment "

"' T(e genera start up procedure is performed' Ma.e sure a -a-e are fu+ cosed'

' $ompressi-e pump is s*itc( on and ao*ed t(e pressure inside t(e c(am/er to increase

up to a/out "23.Pa' T(en, s*itc( off t(e pump and remo-e t(e (ose from t(e c(am/er'

0' T(e pressure reading inside t(e c(am/er is monitor unti t(e reading sta/ii4es'

1' T(e pressure reading for /ot( c(am/ers is recorded /efore expansion'

2' #pen 53 fu+ and ao*ed t(e pressuri4ed air fo* into t(e atmosp(eric c(am/er'

6' T(e pressure reading for /ot( c(am/ers after expansion is recorded'

7' T(e experiment is repeated under difference condition:

a8 9rom atmosp(eric c(am/er to -acuum c(am/er'

/8 9rom pressuri4ed c(am/er to -acuum c(am/er'

' T(en, cacuated t(e P5 -aue and pro-e t(e ;o+es< =a*'

Experiment 0

"' T(e genera start up is perform ma.e sure a -a-e are fu+ cosed'

' T(e (ose form compressi-e pump is connected to pressuri4ed c(am/er'


3/13

0' T(e compressi-e pump is s*itc( on and ao*ed t(e pressure inside t(e c(am/er to

increase unti a/out "63.Pa' T(en, s*itc( off t(e pump and remo-e t(e (ose from t(e

c(am/er'

1' T(e pressure reading inside is monitor unti it is sta/ii4es' T(e pressure reading PT" and

temperature reading TT" are recorded'

2' T(en, open t(e -a-e 5 3" sig(t+ and ao* t(e air fo* out so*+ unti it reac(

atmosp(eric pressure'

6' T(e pressure of t(e reading and t(e temperature reading after t(e expansion process are

recorded'

7' T(e isentropic expansion process is discussed'

Experiment 1

"' Perform t(e genera start up procedures' Ma.e sure a -a-e are fu+ cosed'

' T(e (ose is connected from t(e compressi-e pump to t(e pressuri4ed c(am/er'

0' T(e compressi-e pump is s*atc( on and ao*ed t(e pressure inside t(e c(am/er to


c(am/er'

1' T(e pressure reading is monitor unti it is sta/ii4es' Recorded t(e pressure reading PT"'

2' T(e -a-es 5 3" is open fu+ and /ring it /ac. to t(e cosed position instant+' Monitor

and recorded t(e pressure reading PT" unti it /ecame sta/e'

6' Repeated step2 for at east 1 times'

7' T(e pressure is dispa+ on t(e grap( and discuss'

Experiment 6

"' Perform t(e genera start up procedure' Ma.e sure a -a-e is cose

' T(e compressi-e pump is s*itc( on and ao*s t(e pressure inside t(e c(am/er increase

up to "23.Pa' T(en, s*itc( off t(e pump and remo-e t(e (ose from t(e c(am/er'

0' T(e pressure reading inside t(e c(am/er is monitor unti it sta/ii4es'

1' T(e pressure reading for /ot( c(am/ers /efore t(e expansion is recorded'

2' T(e 5 3 is open and ao*s t(e pressure air fo* into t(e atmosp(eric c(am/er so*+'

6' T(e pressure reading for /ot( c(am/ers after t(e expansion is recorded'


4/13

7' T(e experiment procedure is repeated for difference condition

a8 9rom atmosp(eric c(am/er to -acuum c(am/er'

/8 9rom pressuri4ed c(am/er to -acuum c(am/er'

' T(en, t(e ratio of t(e -oume is cacuated and compare *it( t(e t(eoretica -aue'

Experiment 7

"' T(e genera start up is performs' Ma.e sure a -a-e is fu+ cose'

' T(e compressi-e pump is connected to pressuri4ed c(am/er'

0' T(e compressi-e pump is s*itc( on and ao*s t(e pressure inside t(e c(am/er to


c(am/er'

1' T(e pressure reading inside t(e c(am/er is monitor unti is sta/ii4ed' T(e recorded t(e

pressure reading PT" and temperature TT"'

2' #pen t(e -a-e 5 3" fu+ and /ring it to cose unti after a fe* seconds' Monitor and

recorded t(e reading PT" and temperature TT" unti it /ecome sta/e'

6' T(e ratio of t(e (eat capacit+ is determines and t(en compare *it( t(e t(eoretica -aue'

>'


5/13

RESULT

Experiment 1: Boys Law Experiment

$ondition T+pes of $(am/er Pressure ?.pa8 Temperature ?o$8

;efore Expansion 5acuum "3'> 2'Pressure "0' 2'6

After Expansion5acuum "6'3 2'"

Pressure "6' 6'1

Ta/e: Pressure reading for /ot( c(am/ers /efore and after expansion

Experiment 3: Isentropic Expansion Process

$ondition Pressure, PT" ?.Pa8 Temperature, TT" ?o$8

;efore Expansion "2"'> 7'"

After Expansion "30'2 2'"

Ta/e: T(e pressure and temperature reading in pressuri4ed c(am/er

Experiment 4: Stepwise Depressuriation

Pressure, PT" ?.Pa8

;efore

Expansion

After Expansion

"st Tria ndTria 0rd Tria 1t( Tria

"20'> "7'0 """'2 "31'2 "30'


6/13

1st Expansion 2nd Expansion 3rd Expansion 4th Expansion0

20

40

60

80

100

120

140

Response of pressuri4ed -esse foo*ing step*ise depressuri4ation

Expansion

Pressure (kPa)

Experiment !

Pressure?.Pa8

Part PT " PT

;efore expansion After expansion ;efore expansion After expansion

PT " to PT "12' "0"'" "32'6 ">'2

PT to PT " "31'" ""7'> "12'2 ""7'3

Experiment "

;efore expansion After expansion

Pressure ?.Pa8 "21' "3'

Temperature ?o$8 2'1 6'7

S#$PLE %& '#L'UL#TI%(


7/13

Experiment 1: Boy)es Law Experiment

Idea gas e)uation, P5@RT'

9or ;o+e'"2 2B$

!ence, R@ '0"1L. kPa

K . mol

9or Pressure -esse:

;efore expansion @ "0' .Pa,

After Expansion @ "6' .Pa'

T(en 5"and 5is cacuated

5" @RT

P1

@(8.314 L.kPaK . mol ) (298.15K)(1mol)

138.8kPa

@ "7'6 =

5 @RTP

2

@(8.314 L.kPaK . mol ) (298.15K)(1mol)

126.8kPa

@ ">'22 =

;+ using ;o+e


8/13

P"5" P5?pro-ed8

T(e difference /et*een P"5" and P5 is on+ 3'3, (ence, t(e ;o+e


9/13

Experiment 3: Isentropic Expansion Process

T2

T1

=P

2

( k1k

)

P1

TCT"@ ?PC P"8?.&" C .8

?2'"8 C ?7'"8 @ ?"30'28 C ?"2"'>8?.&" C .8

3'>6 @ ?3'6"18?.&" C .8

n 3'>6 @ ?.&"8C . n 3'6"1

&3'3767 @ ?.&"8C.?&3'0068

3'">>> @ ?.&"8C.

* + 1,34

T(e difference is ?"'1&"'018 x "33 @ 6F

G(ere

actua . @ "'1

t(eoretica . @ "'01

Experiment !

"8 Pressure c(am/er to -accum c(am/er

P"5"@ P55C 5"@ P"C P5C 5"@ "0"'"C "12'

5C 5"@ 3'>30


10/13

In -acuum c(am/er:

P"5"@ P55C 5"@ P"C P5C 5"@ "32'6 C ">'2

5C 5"@ 3'"2

T(eoretica -aue

5 C 5"@ "2 C 2

@ 3'6

8 Atmosp(eric c(am/er to -accum c(am/er

P1V1= P2V2

V2/ V1= P1/ P2

V2/ V1= 104.1 / 117.0

V2/ V1= 0.88

Experiment ": Determination o- .eat 'apacity

he expression o! heat "apa"it# ratio is$

Cv

R ln

T2

T1= %&n

V2

V1

'here(V

2

V1=

P1T

1

P2T2

Cv

8.314L.kPa

K . mol

ln298 .55K

299.85K=

%&n(154.2kPa)(298.55K)(108.8kPa)(299.85K)


11/13

)* = 66+.88L. kPa

K . mol

)p= )*, -

)p= 66+.88L. kPa

K . mol, 8.314

L . kPa

K . mol

= 674.204L. kPa

K . mol

here!ore( the ratio is$

Cp

CV =

(674.204 L.kPa

K . mol)

(665.8 L.kPa

K . mol)

= 1.026

he theoreti"a& *a&ue o!C

p

CV is 1.4

Per"entae error =Theoretical valueActual value

Actual value x 100

=1.41.026

1.026 x 100

= 36.40


12/13

DIS'USSI%(

According to =ange,">6>, ;o+e


13/13

t(e resuted -aue of (eat capacit+ ratio and t(e t(eoretica -aue is a/out 06'1"F' T(is -aue

aso de-iated )uite muc( from t(e t(eoretica -aue and can /e expained /+ t(e accidenta

mista.es done'

"8 Nor/ert A' =ange '">6>' =ange

result discussion lab 5 thermo

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