simple tests

Scan First – Thermodynamics 1/28

Simple tests

To be done after reading and learning the lecture.

Content :

Chapter I................................................................................................................................. 2 Chapter II ............................................................................................................................... 4 Chapter IV.............................................................................................................................. 7 Chapter V ............................................................................................................................... 9 Chapter VI............................................................................................................................ 16 Chapter VII........................................................................................................................... 20 Chapter IX............................................................................................................................ 23

january 2011


Chapter I

Pressure and temperature The ideal gas

1. What are the different assumptions used to define the ideal gas ?

2. Define the so-called "standard and normal conditions of temperature and pressure". What is

the molar volume of gas in such conditions ? Find the value of the universal gas constant in

SI. What is the unit ?

3.An electronic tube is sealed under vacuum at 27°C under a pressure of 1.2 10-5 torr. The

volume of the tube is equal to 100 cm3. How many molecules are trapped in the tube ?

4.A given quantity of gas fills a volume of 200 cm3 at CNTP. What would be the volume at

273°C under 4 atm ?

5.What is the density of methane 4CH at 27°C under 4 atm ?

6.What is the specific gravity with respect to air of carbon monoxide under 2.5 atm at -20°C ?

7.A mixture of gases is made of 65wt% nitrogen, 15wt% hydrogen, and 20wt% carbon

dioxide. The total pressure is 760 torr. Give the molar fractions of the three gases. Calculate

the partial pressures.

8.Air is constituted of approximately 80 mol% of nitrogen and 20 mol% of dioxygen. 4 g of

dihydrogen is injected in a florence flask of 22.4 L, initially filled with air under 1 atm. The

temperature is maintained constant at 0°C. What is the mean molar weight of the air-

dihydrogen mixture ?

9.Give in Pascal the value of the following units of pressure

(a) atmosphere, (b) torr, (c) bar.


Answers

3 - N = 5

23 130

0 0

1.210 0.1 2736.0210 3.8610

760 22.4 300A

TP VN

P V T

;

4 - 300

0

50cmP T

V VP T

;

5 - 100

0

16 4 2732.6g litre

22.4 1 300

TP

TP ;

6 - The specific gravity with respect to air is independent on the conditions of temperature

and pressure 28

0.96629 29

Md .

7 - 2 2 20.22 ; 0.712 ; 0.068N H COx x x ;

2 2 2167 Torr ; 541 Torr ; 51.5TorrN H COP P P .

8- 2 2 20.8 ; 2 ; 0.20N H On n n

0,8 0,2 2

28 32 2 10.93g3 3 3

M .

9 - 1 Torr = 133.3 Pa


Chapter II

Generalities

Systems, states, properties, thermodynamic processes

1- Phases and compounds

A. select the correct answer : "the number of compounds of a system" :

a) is always equal to the number of phases,

b) is always lower than the number of phases

c) is always larger than the number of phases

B. answer by "wrong" or "right"

a) There exists no general relationship between the number of compounds and the number of

phases of a system,

b) mixing two liquid phases, always gives one liquid phase,

c) cooling a liquid blend always gives a single solid phase, called solid solution,

d) mixing two gases always gives a single gas phase.

2- Systems

answer "right" or "wrong".

A. a closed system transfers to the surroundings :

(a) no heat (b) no work (c) neither work nor heat

(d) no matter (e) only matter (f) only heat

B. Same question for an isolated system

C. Same question for an open system

3- (a) What are intensive and extensive variables ?

(b) sort out intensive and extensive variables : pressure, temperature, volume, mass, electric

charge, electric potential, potential energy.

4- Are the following properties tensions ?

(a) volume, (b) pressure, (c) temperature

5- The variation of a state variable during a transformation depends on the process. Right or

wrong ?


6- During a closed process,

(a) there is no exchange of work,

(b) there is no exchange of heat,

(c) there is no energy exchange,

(d) the state of the system can not be described,

(e) none of these answers above are correct (give the correct definition)

7- During an open process,

(f) the system exchanges neither work nor heat,

(g) the system initial and final states are different,

(h) matter can be exchanged

8- Are the following processes reversible, quasi-static or irreversible ?

(i) braking of a vehicle,

(j) drying of clothes

(k) very slow compression of a gas by a piston sliding without friction in a cylinder.

(l) vaporisation of water at 100°C under 1 atmosphere.

(m) very slow compression of gas by a piston sliding with friction against a cylinder wall.

(n) very slow traction on an elastic

(o) extension of a spring due to a mass (dropped)

(p) loading of a capacitor, previously discharged, with a battery.

9- During an isochoric process the temperature of the system remains constant. Right or

wrong ?

10- Consider a vehicle moving at a speed V (state A), then in final state B, the vehicle brakes

and stops.

A wheel of the vehicle is submitted to a process that is :

(a) isothermal, (b) "monothermal" (c) isobaric (d) isochoric

(e) irreversible (f) reversible (g) adiabatic

Some answers may be discussed, why ?

11- What is the sign convention used to describe the energy exchange between a system and

the surroundings ?


Answers

1 - A a),b), c) no B a) true b),c) wrong , d) true

2 - A) closed system : d) true, other answers wrong

B) isolated system : a), b), c), d) true

C) open system : none, transfer both energy and matter

3 - a) see course, b) intensive variables : pressure, temperature, electric potential..., other

quantities are extensive.

4 - b) c) yes

5 - wrong

6 - e) closed process : identical initial and final states

7 - b)

8 - irreversible : a), b), g, h) ; quasi-static : e) ; reversible : c), d) f).

9- wrong

10- a) no, b) yes after the wheel temperature is back to 20°C, c) no if one consider the stress

induced by the brake on the wheel; d) yes, if the thermal expansion of the wheel is neglected,

e) yes; f) and g) no.

:


Chapter IV

The first law

1- A system receives a heat quantity of 350 J. It supplies to the surroundings a work of 400 J.

What is its internal energy variation ?

2- At state A, a quantity of 200 kg of water is moved in translation at a speed of 2 ms-1 , its

altitude is 20 m. At state B the height is 10 m and the velocity is 6 ms-1. It receives a work of

25 kJ and it supplies a heat quantity of 8 kJ during the AB process. Calculate its internal

energy variation B AU U U ?

3- Right or wrong ?

a) dU dW dQ

b) U W Q

c) U W Q

d) U W Q

e) U W Q

f) dU W Q

4- Right or wrong ?

Consider a system characterised by three variables X, Y and Z related by a state equation.

a) for any process , ,dX dY dZ , one can define dU dX dY dZ ,

b) for any process , ,dX dY dZ , one can define dU AX BY ,

c) ,X Y

UA

X

d)

X

UA

Y

e)

Y

UA

X

5- Give the three hypotheses used to establish : H U nRT and the meaning of n


answers

1 - 50 JU

2- The macroscopic mechanical energy variation is

2 2,

1( ) 16800 J

2m macro B A B AE m V V mg h h

,m macroW Q E U 16800 25000 8000 33800 JU

3- a) wrong

b) wrong

c) right

d) wrong

e) wrong

f) right

4- a) wrong because only two variables are independant

b) right

c) wrong :

d) wrong

e) true


Chapter V

Application of the first law

A Calorimetric coefficients

1- Give the dimensions of the coefficients VC , PC , and h in terms of the fundamental

units (length, mass, time and temperature), give the usual expression in IS units, and specify

their intensive or extensive nature.

2- We recall : 2

P V

T

TVC C

where T is temperature, V molar volume, isobaric

expansion coefficient and T the isothermal compressibility coefficient of a body.

(a) define and T . Calculate their value for an ideal gas.

(b) Show that the above general relation leads to P VC C R .

(c) given at 298 K :

2H O ( 18 gM ) : 4 -12.410 K , -31g cm , 10 -14.610 PaT , -1 -175.2 Jmol KPC

Al ( 27 gM ) : 6 -12310 K , -32.7 g cm , 11 -11.3310 PaT ,

-1 -124.3 Jmol KPC

Calculate P VC C in these two above cases and compare to b)

3- Consider one mole of an ideal gas in the CNTP. What is the quantity of heat exchanged

during a reversible isothermal compression where :

(a) 0.01 LV (b) 10 LV (c) 1 LV

Discuss the strategy adopted to evaluate V depending on its value (use the definition of Q

or the calculation presented in §B1-2.

4- Consider one mole of an ideal gas in the CNTP. What is the quantity of heat exchanged

during a reversible isothermal compression where :

(a) 10 PaP (b) 4510 PaP

Again, discuss the strategy adopted to evaluate P depending on its value.

5- Using equations of §III-2 and data of above test 2 :

(a) show :T

T


(b) express h in terms of T , and V . Calculate the numerical values of and h for water.

(c) evaluate the heat quantity during an isothermal reversible process inducing :

(i) a decrease of 0.04% of the molar volume (relative value approximately equal to that of test

3-a)

(ii) a pressure increase of 5.104 Pa (identical to test 4-b).

Compare the numerical results to those corresponding in tests 3 an 4.

6- A metallic bloc A of mass Am , molar mass AM , molar heat capacity PAC at temperature

AT is deposited on a bloc B ( Bm , BM , PBC , BT ), so that they are in contact and isolated from

the surroundings. Evaluate the final temperature fT , supposing that A BT T .

7- What is the quantity of heat required to rise the temperature of one mole of CO2 between

300 and 400 K ? Use the data proposed above in chapter V.

B- ideal gas processes

8- right, wrong, why ?

a) During an adiabatic transformation, temperature remains constant since the system does

not exchange heat with the surroundings.

b) A process is isothermal if no heat is exchanged between the system and the surroundings.

c) Reversible an irreversible adiabatic expansion of an ideal gas is associated to a decrease of

its internal energy.

d) isothermal compression of an ideal gas is associated to an increase of its internal energy.

9- What is the supplied work to decrease the volume of 2 moles of an ideal gas in the STP of

75% at constant temperature. What is the heat exchanged with the surroundings. Precise the

direction of the transfer.

10- 50 L of ideal gas is embedded under a pressure of 2 atm in a cylinder closed by a piston.

The piston is unlocked and the gas abruptly expands, then after a while the system is again at

thermodynamic equilibrium, at a final temperature identical to the initial one. Calculate the

exchanged work and heat with the surroundings.

11- From the definition of an adiabatic process, establish the equation relating P and

V during a reversible adiabatic process. Deduce the equation relating P and T .

12- Calculate the ratio of the slopes in the Clapeyron diagram of an isotherm and the

adiabatic at the same point ( , )P V .

13- 1 mole of an ideal gas in the CNTP is submitted to an adiabatic expansion down toa

pressure of 0.5 atm. Calculate :


- the final volume,

- the work of the gas,

- the final temperature,

- the internal energy variation.

C Thermochimistry

14- An athermal reaction :

a) is used to product heat b) can not processed if heat is not provided

c) exhibits a null heat exchange d) none of these definitions is correct

15- The heat of reaction of process leading a system from a state A to a state B is defined for

a process A B

a) isochoric b) monothermal ( A BT T ) c) isobaric d) isothermal

16- The heat transferred to a close system during a chemical reaction processed at constant

pressure (or constant volume) is equal to the enthalpy variation (internal energy) of the

system.

17- Calculate 298 298r rH U for the following reactions and sort them out :

a) C6H6(l) C6H6(g)

b) Fe2O3 (s) + 3 CO(g) 2 Fe(s) + 3 CO2(g)

c) (NH4)2SO4(s) 2 NH3(g) + H2O(g) + SO3(g)

d) C2H4(g) + 3 O2(g) 2 CO2(g) + 2 H2O(l)

18- The standard state of a body is

a) a unique state defined at 298 KT and 1 atmoP

b) a unique state defined at 298 KT and 1 baroP

c) a state defined for a temperature T under the pressure of 1 bar.

c) a state defined for a temperature T under the pressure of 1 atm.

19- The standard reference state of an element at temperature T is :

a) always the ideal gas state at temperature T under the pressure of 1 bar,

b) generally the physical state of the most stable simple compound at temperature T under the

pressure of 1 bar.

20- from :

N2O3(g) NO(g) + NO2(g) (1) rH298(1) = 39,6 kJ.mol-1

2 NO2(g) N2O4(g) (2) rH298(2) = - 57,2 kJ.mol-1

Calculate the reaction enthalpy of : 2 NO(g) + N2O4(g) = 2 N2O3(g)


21- Between the different possibilities, which one is the standard formation enthalpy of

copper sulfate ?

Cu2+(sol) + SO42-(sol) CuSO4(s)

Cu(s) + SO2 (g) + O2(g) CuSO4(s)

Cu(s) + S(s, orthorh) + 2 O2(g) CuSO4(s)

Cu (s) + S(s, orthorh) + 4 O(g) CuSO4(s)

Does it mean that copper sulfate is prepared from this reaction ?

22- Calculate the heat of combustion in excess of oxygen of Al(s), C(s, graphite), H2(g),

CH4(g) et CH3OH(l), supposing the produced water liquid. Consider the isobaric reaction heat

to be equal to the standard reaction enthalpy. Use the data table in the exercise book.

23- physical state transformation, answer by right or wrong :

(a) The latent heat corresponding to the physical state transformation of a substance is the

molar enthalpy variation during the transition.

(b) Depending on the substance, fusion is either endo- or exothermic.

(c) Fusion and sublimation are always endothermic.

(d) Crystallisation may be exothermic.

(e) Fusion, vaporisation and sublimation are always endothermic.

(f) Latent heats are independent of the temperature.


answers

1 – [CP] or [CV] 2 -2 -1energiemL t T

Q

T T

; Joules. K-1 ; extensive (since T is intensive)

-22 -2 -3

2

mL tenergie forcemL t L = =pression

surfaceL

Q

V V

A ; Pascal ; intensive (since V is

extensive)

2 -23

-1 -2

mL tenergie= =L =volume

mL t

Qh

P P

; m3 ; extensive (since P isintensive).

2 – .a) see course

b) give and T their value for the ideal gas.

c) idal gas

P VC C 8.32 J.mol-1K-1.

318cmwaterV ; 26 4

10water

298 18.10 2, 4.10

4,6.10P VC C

= 0.67 J.mol-1K-1.

31 cmAlV ; 26 5

11Al

298 1.10 2.310

1.3310P VC C

= 0.011 J.mol-1K-1.

Conclusion : quantitatively, andP VC C are closer when the state is more condensed and the

substance of low compressibility.

3 -

a) The volume variation being low and Q equivalent to an elementary variation, Q, one can

write Q = V = P V = 1.013.105 .(- 10-5) = - 1.013 J.

b) can not be considered constant ( = P) and must be integrated.

111.4

ln 8.32 273ln22.4

frev

i

VQ nRT

V = -1343 J.

c) For this intermediary case the approximated calculation leads –101,3 J, while the more

exact one –103,7J. The approximation remains correct until few percents.

4 - a) The pression variation being weak, Q can be considered an elementary variation :

Q = hP = - V P = - 22.4.10-3 . 10 = - 0.224 J.


b) h can not be considered constant (h = -V) and must be integrated.

11.013

ln 8.32 273ln1.513

irev

f

PQ nRT

P = - 911 J.

5 2

P VT T

TV TC C V

water =4

10

298 2.410

4,610

= 1.55 108 Pa

T Th

V h V TV

hwater = - 298.18 10-6 .2.4 10-4 = -1.29 10-6 m3

- a) Q = V = 1,55 . 108. (- 18.10-6 . 4.10-4) = 1,116 J ( and T supposed constant, v

being low)

-b) Q = h P = -1.29 10-6.5 104 = -0.0645 J. (Same remarks, the compressibility of the liquid

being weak, V can be considered constant).

6- Heat quantity supplied by the hot block = heat quantity received by the cold block

A BPA PBA f f B

A B

m mC T T C T T

M M

A BPA PBA B

A Bf

A BPA PB

A B

m mC T C T

M MT

m mC C

M M

7 – PC CO2 = 44.10 + 9.03 10-3T - 8.53 105T-2 J.K-1.mol-1

Q = 400 5

32

300

8.531044.1 9.0310dT TdT dT

T

2 2

3 5(400) (300) 1 144.1 400 300 9.0310 8.5310

2 400 300Q

= 4015 J.

B – Ideal gas processes.

8 - a) wrong b) wrong c) true since W < 0 and U < 0 d) wrong U = 0

(isothermal)

9 – ln 2 8.32 273ln 4 6300 Jirev

f

VW nRT

V Qrev = - 6300 J


10 – Vf = 100 L ; Wirr = -Pf (Vf – Vi) = - 5065 J ; Qirr = - Wirr = 5065 J

13 – Diatomic gas : = 1,4 ;

1/

if i

f

PV V

P

= 36.75 L

21 1( ) (0.5 36.75 22.4) 10

1 0.4f f i iW P V PV

- 1006 J

( )v f iW C T T or PfVf = R Tf Tf 221 K

C) - Thermochimistry

14 c)

15 b)

16 yes

17 c>a>b>d (compare ng)

20: -22.0 kJ.mol-1

21: the third, no.

22- 31.05 ; - 32.76 ; - 141.8 ; - 55.50 ; - 22.7 (heat supplied to the surroundings)


Chapter VI

The second law

1. Consider a boat near the tropics. It transfers heat from the warm sea water which is directly

transformed into mechanical energy for the boat motion and it rejects ice to the sea. Is it

possible ?

2. A system (ideal gas) follows a Carnot's cycle (two adiabatic and two isothermal

processes) and supplies a work of 300 J. The reservoir temperatures are respectively

1 450 KT and 2 300 KT . Calculate the heat quantities 1Q and 2Q exchanged between the

system and the reservoirs, give their sign. Calculate the energy fraction transformed to work.

3. A system of entropy S is processed from an equilibrium state A to a final

equilibrium state B through two different processes, one reversible and the other one

irreversible. we can write :

a) irr revS S

b) irr revS S

c) irr revS S

d) none of these answers. We must describe both processes to decide.

4. Right or wrong ? The second law expresses :

a) the energy conservation,

b) the entropy conservation,

c) the disorder conservation,

d) the irreversible evolution of the universe to an increasing state of disorder,

e) the irreversible evolution of a system to an increasing state of disorder.

5. Right or wrong ? For any process, the second law requires the entropy variation of a system

to be : a) positive or nil, b) negative or nil,

c) positive, d) No requirement is imposed by the second law to a system.


6. Right or wrong ? Entropy

a) is a state function,

b) is an intensive quantity,

c) of the universe can be created but not destroyed,

d) of a system can vary only if there is energy transfer to the surroundings,

e) of an isolated system is constant,

f) of a pure substance at a unique microscopic configuration is nil at 0K.

7. Right or wrong ?

a) Consider a thermal reservoir at temperature T , supplying the heat quantity Q to a system.

Its entropy variation is /Q T , whatever the conditions (reversible or irreversible) of heat

transfer.

b) A reversible work transfer does not lead to entropy variation.

c) A heat quantity of 300 J is transferred from a reservoir at 300 K to a system at the same

temperature. What is the entropy variation of the system ?

8. 100 g of water is heated from 25°C to 80°C, calculate the entropy variation.

9. The vaporisation of water at 100°C under a pressure of 1 atmosphere is a -------------

process. Calculate the entropy variation of 1 mole of water evaporating in these conditions

(The corresponding enthalpy is 0 -1398 2300 kJ kgH H ).

10. Two identical solids of identical heat capacities -1100 JK at initial temperatures of

1 700 KT and 2 300 KT respectively are connected. We suppose that they are perfectly

isolated from the surroundings. Describe the final equilibrium state, calculate the entropy

variation between the two states and comment on it.

11. During the isothermal reversible expansion of an ideal gas,

a) the internal energy remains constant,

b) there is no heat transfer owing to the isothermal nature of the process,

c) the entropy of the surroundings remains constant,

d) the gas entropy increases,

e) the entropy of the universe remains constant.


12. Calculate the entropy variation of one mole of ideal gas submitted to a reversible

isothermal compression from 1 atm to 3 atm at 25°C.

13. An adiabatic process always operates

a) at constant internal energy,

b) at constant enthalpy,

c) at constant entropy,

d) none of these answers.

14. Right or wrong?

a) The heat transferred to the surroundings in the case of an irreversible adiabatic process is

not nil, contrary to the reversible case, but it is low.

b) The entropy variation of the system is negative and that of the surroundings positive.

c) The entropy variation of the system is positive and that of the surroundings negative.

d) none of these answers because ----------------.


Answers

1. no

2. 1 900 JQ , 2 600 JQ .

3. a)

4. only d) is true

5. d) true.

6. a), c) and f) true

7. a), b) true c) -110 JKS

8. -170.8 JKS

9. reversible - -10.111 JKS .

10. at equilibrium 1 2 500 KT T , -117.44 JKS

11. a), d) e) true

12. -19.14 JKS

13. d)

14. d)


Chapter VII

Application of the two laws

1- Consider an elementary process of a system of state equation ( , , ) 0f P V T . How many

possible expressions of the heat quantity revQ transferred to the surroundings can be

written ? Detail these expressions and the definition of the corresponding calorimetric

coefficients.

2- Right or wrong (in that case give the correct expression)

Consider a system of state equation ( , , ) 0f P V T ,

a) VV

UC

T

b)

T

Uh

P

c) V

PT

T

d)

T

Vh T

P

3- Right or wrong ?

a) The revCOP of a heat engine only depends on the high and low temperatures of the

reservoirs.

b) The revCOP of a heat pump is lower than unity,

c) The revCOP of a frigorific machine is higher than unity,

d) "COP" and efficiency are equivalent.

4- Calculate the reversible efficiency of a heat machine working with two reservoirs at

temperature 300 K and 500 K?

5- Energy is transferred to a flat by a heat pump with an efficiency of 12. The temperature in

the flat is 20°C and the behaviour is reversible. What is the temperature of the low

temperature reservoir ?

6- An engineer pretends having designed a heat engine working between 200°C and 50°C

with a COP of 0.35. Is this value :

a) normal,


b) this just acceptable,

c) good,

d) excellent ? e) impossible.


Answers

1- three different expressions (two independent variables). see lecture for the two expression

in terms of ,dT dP or ,dT dV .

2- a) right; b) wrong T

Hh V

P

; c) right; d) wrong

P

Vh T

T

3- a) right; b) wrong; c) right; h) wrong; see lecture.

4- 0.4

5- -4.4°C

6- d) 0.37revCOP


Chapter IX

thermodynamics of pure substances

application to phase change

simple tests

1 - right or wrong ?

a) The Gibbs free energy of a system is a state function,

b) it is written G H TS ,

c) for an elementary process : dG SdT PdV ,

d) if F is the Helmoltz free energy of the system G F PV

2 - what are the correct propositions ?

a) The Gibbs free energy is thermodynamic potential because it can predict the evolution of a

system for any process.

b) During a reversible process at constant pressure and temperature, the Gibbs free energy of

a system does not vary.

c) During a process at constant pressure and temperature, the Gibbs free energy of a system

always remains constant.

d) The Gibbs free energy variation A BG of a system between the states A and B is

minimum for a reversible process A B .

e) A spontaneous evolution of a system at constant temperature and pressure always implies a

decrease of the Gibbs free energy.

3 - complete

The molar latent heat of vaporisation of a substance is the heat quantity required to transform

one mole of this substance from the -------- state to the -------- state, at constant -------- and ----

---. This explains on one hand the terms of ------- heat and on the other hand that this

transferred heat corresponds to an -------- variation of the system constituted of one mole of

the substance. This also explains the equivalent name of molar vaporisation ---------- .

4 - terms

a) Name the transformation solid gas, gas liquid, solid liquid and their opposite.

b) What is a supercritical fluid ?


c) Define the terms "boiling curve" and "dew curve".

d) define the "critical point".

5- Complete the following diagram

6- at 0°C, the saturation vapour pressure of CO2 is 34 atm. In these conditions, the molar

volume of liquid and gas CO2 are respectively 45 and 450 cm3. Still under theses conditions

the volume one mole of CO2 is 200 cm3. Calculate the molar ratios of the liquid and the solid.

7- Specify the conditions where the equation 0( ) ( ) lnT TG G RT P is correct.

8- Specify the conditions where the Clapeyron equations are correct :

(a)S SdP

dT V V

(b)

HdP

dT T V V

(c) ln trsH

P CteRT

9- Close to the triple point

the molar sublimation

enthalpy of NH3 is

31.29 kJmol-1, and its

molar vaporisation

enthalpy is 25,68 kJmol-1.

Calculate the molar

solidification enthalpy.

10- complete the following

diagram


Answers

1- a) true, b) wrong, c) wrong, d) true

2- a) wrong, b) true, c) wrong (only true for a reversible process), d) wrong G is a state

function, e) true

3- The molar latent heat of vaporisation of a substance is the heat quantity required to

transform one mole of this substance from the liquid state to the vapour state , at constant

pressure and temperature. This explains on one hand the terms of latent heat and on the other

hand that this transferred heat corresponds to an enthalpy variation of the system constituted

of one mole of the substance. This also explains the equivalent name of molar vaporisation

enthalpy.

4- cf course

5-

6- lever rule : 200 45

0.383450 45vx

1 0.617l vx x

7- cf course

8- a) and b) always true, c) only true for the equilibrium curve between a condense phase and

vapour, considered as an ideal gas, if the volume of the condense phase is neglected and

H independent of temperature.

9- 13( ) 5.61 kJmolsol H NH

10- see course

boiling curve dew curve

vapour +liquid vapour

liqui

d

supercritical fluid

T

P

T1

T6

critical point

VI - the second law 27

simple tests

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