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CBSE Questions for Class 11 Medical Chemistry Thermodynamics Quiz 16 - MCQExams.com

For a system in equilibrium, ΔG=0 under conditions of constant:
  • temperature and pressure
  • temperature and volume
  • pressure and volume
  • energy and volume
At what value of α will the heat capacity be negative?
  • α<1
  • α<0
  • α>γγ1
  • α<γ
What is the heat capacity of the ideal monoatomic gas undergoing the process shown in the figure?
1679147_62b3c842a8db4ad090b1ef604c15fe2d.png
  • 1.5R
  • 2.5R
  • 3.5R
  • 1.33R
For which of the following gases, the difference in specific heats at constant pressure and at constant volume is equal to 0.04545cal?
  • N2
  • N2O
  • CO
  • CO2
Which of the following statement(s) is/are incorrect?
  • The specific heat capacity of a substance is greater in the solid-state than in liquid state.
  • The specific heat capacity of a substance is greater in gaseous state than in the liquid state
  • The latent heat of vaporization of a substance is greater than that of fusion
  • The internal energy of an ideal gas is a function of its temperature
The standard heat of combustion of propane is 2220.1 kJ/mol. The standard heat of vaporization of liquid water is 44 kJ/mol. What is the Ho of the reaction :
C3H8(g)+5O2(g)3CO2(g)+4H2O(g)?

  • 2220.1 kJ
  • 2044.1 kJ
  • 2396.1 kJ
  • 2176.1 kJ
For a specific work, on an average a person requires 5616 kJ of energy. How many kilogram of glucose must be consumed if all the require energy has to be derive from glucose only? ΔH for combustion of glucose is 2808 kJ mol1
  • 0.720 kg
  • 0.36 kg
  • 0.18 kg
  • 1.0 kg
The value of Hsol of anhydrous copper (II) sulfate is 66.11 kJ. Dissolution of 1 mole of blue vitriol (Copper (II) sulphate pentahydrate) is followed by absorption of 11.5 kJ of heat. The enthalpy of dehydration of blue vitriol is: 
  • 77.61 kJ
  • +77.61 kJ
  • 54.61 kJ
  • +54.61 kJ
The data below refers to gas phase reaction at constant pressure at 25oC.
CH3CH3CH3CH2+H;H1=+420 kJ mol1
CH3CH2CH2=CH2+H;H2+168 kJ mol1
From these data, the enthalpy change H for the reaction : 2CH3CH2CH3CH3+CH2=CH2 is 
  • +250 kJ
  • +588 kJ
  • 252 kJ
  • 588 kJ
Geological condition are sometimes so extreme that quantities neglected in normal laboratory experiments take on an overriding importance. For example, consider the formation of diamond under geophysically typical conditions. The density of graphite is 2.4 g/cm3 and that of diamond is 3.6 g/cm3 at a certain temperature and 500 kbar. By how much does ΔUtrans differes from ΔHtrans for the graphite to diamond transition?
  • 83.33 kJ/mol
  • 0.83 kJ/mol
  • 8.33×107 kJ/mol
  • 83.33 J/mol
A quantity that cannot be directly measured is:
  • heat of formation of H2O(l)
  • heat of formation of CH4(g)
  • latent heat of fusion of ice
  • heat of combustion of ethyl alcohol
Enthalpy of  neutralization of oxalic acid is 25.4 kcal/mol using strong base, NaOH. Enthalpy change for the process:
H2C2O4(aq)2H+(aq)+C2O24(aq) is about
  • 2.0 kcal
  • 11.7 kcal
  • 1.0 kcal
  • 4.0 kcal
For a spontaneous process:
  • enthalpy change of the system must be negative
  • entropy change of the system must be positive
  • entropy change of the surrounding must be positive
  • entropy change of the system plus surrounding must be positive
The reaction is ?
  • spontaneous and exergonic
  • non-spontaneous and exergonic
  • spontaneous and endergonic
  • non-spontaneous and endergonic
When we take acetone in a test tube it feels cold. Which reaction occurs in the process?
  • endothermic reaction
  • exothermic reaction
  • reversible process
  • adiabatic process
In an ice calorimeter, a chemical reaction is allowed to occur in thermal contact with an ice-water mixture at 0oC. Any heat liberated by the reaction is used to melt some ice; the volume change of the ice-water mixture indicates the amount of melting. When solutions containing 1.0 millimole each of AgNO3 and NaCl were mixed in such a calorimeter, both solution having been pre-cooled to 0oC, 0.20 g of ice-melted. Assuming complete reaction in this experiment, what is ΔH for the reactions: Ag+(aq)+Cl(aq)AgCl(s) ? Latent heat of fusion of ice at 0oC is 80 cal/g.
  • 16 kcal
  • +16 kcal
  • 16 cal
  • +16 cal
Which of the following salts shall cause more cooling when one mole of the salt is dissolved in the same amount of water ? (Integral heat of solution at 298 K is given for each solute.)
  • KNO3;H=35.4 kJ/mol
  • NaCI;H=5.35 kJ/mol
  • KOH;H=55.6 kJ/mol
  • HBr;H=83.3 kJ/mol
For an ideal solution containing two liquid components A and B, the Gibbs free energy of mixing is minimum, when the molar ratio of the liquids is 
  • 1 : 1
  • 1 : 2
  • 1 :10
  • 1 : 1000
Ethyl chlorine is prepared by reaction of ethylene with hydrogen chloride as:

C2H4(g)+HCl(g)C2H5Cl(g);ΔH=72.3 kJ

What is the value of ΔU(in kJ) if 70 g of ethylene and 73 g of HCl are allowed to react?
  • 69.8
  • 180.75
  • 174.5
  • 139.6
The factor of G values is important in metallurgy. The G values for the following reactions at 800oC are given as :
S2(s)+2O2(g)2SO2(g);G=544 kJ
2Zn(s)+S2(s)2ZnS(s);G=293 kJ
2Zn(s)+O2(g)2ZnO(s);G=480 kJ
The G for the reaction : 2ZnS(s)+3O2(g)2ZnO(s)+2SO2 will be 

  • 357 kJ
  • 731 kJ
  • 773 kJ
  • 229 kJ
For the reaction, A(s)+3B(g)4C(s)+D(l).
ΔH and ΔU are related as:
  • ΔH=ΔU
  • ΔH=ΔU+3RT
  • ΔH=ΔU+RT
  • ΔH=ΔU3RT
In the reaction for the transition of carbon in the diamond form to carbon in the graphite form, ΔH is -453.5 cal. This points out that 
  • graphite is chemically different from diamond
  • graphite is as stable as diamond
  • graphite is more stable than diamond
  • diamond is more stable than graphite
10lt box contains O3 and O2 at equilibrium at 2000K. The Go=534.52kJ at 8 atm equilibrium pressure. The following equilibrium is present in the container
2O3(g)3O2(g). The partial pressure of O3 will be (ln 10=2.3,R=8.3J mole1K1).
  • 8×106
  • 22.62×107
  • 9.71×106
  • 9.71×102
Conditions of standard state used in thermochemistry is?
  • 0C and 1 atm
  • 20C and 1 atm
  • 25C and 1 atm
  • 0 K and 1 atm
C+O2CO2+94.2kcal
H2+1/2O2H2O+68.3kcal

CH4+2O2CO2+2H2O(g)+210.8kcal

Then the possible heat of formation of methane will be 

  • 47.3 kcal
  • 20.0 kcal
  • 45.9 kcal
  • -47.3 kcal
In a thermodynamic system working subtance is ideal gas, its internal energy is in the from of
  • Kinetic energy only
  • Kinetic and potential energy
  • Potential energy
  • None of these
Which of the following is slow process
  • Isothermal
  • Adiabatic
  • Isobaric
  • None of these
Gibb's free energy (G) is defined as:
  • ΔG=ΔHTΔS
  • ΔG=ΔH+TΔS
  • ΔH=ΔGTΔS
  • ΔG=ΔH+T×CP
In the Born-Haber cycle for the formation of solid common salt (NaCl), the largest contribution comes from :
  • the low ionization potential of Na
  • the high electron affinity of Cl
  • the low Hvap of Na(S)
  • the lattice energy
If enthalpy of an overall reaction XY along one rout is ΔH and ΔH1,ΔH2,ΔH3,.... representing enthalpies of reactions leading to same product Y then ΔH is
  • ΔH=ΔH1+ΔH2+ΔH3...
  • ΔH=ΔH1×ΔH2×ΔH3...
  • ΔH=ΔH1+ΔH2ΔH3....
  • ΔH=ΔH1×ΔH2×ΔH32....
The statement "The change of enthalpy of a chemical reaction is same whether the reaction takes place in one or several steps" is
  • Le Chatelier's law
  • van't Hoff's law
  • first law of thermodynamics
  • Hess's law.
A reaction proceeds through two paths I and II to convert XZ
What is the correct relationship between Q,Q1 and Q2?
1842300_007866dc9a4a41448cc4609c7a1bc1ac.png
  • Q=Q1×Q2
  • Q=Q1+Q2
  • Q=Q1Q2
  • Q=Q1/Q2
A gaseous system is initially characterised by 500 mL volume and 1 atm pressure at 298 K. This system is allowed to do work as
(i) In isobaric conditions it expands to 800 mL resulting a decrease in pressure and temperature to 0.6 atm and 273 K respectively.
(ii) In adiabatic conditions it is allowed to expand upto 800 mL and results a decrease in pressure and temperature to 0.6 atm and 273 K respectively.

If Glibbs energy change in (i) ΔGa and in is ΔGb then what will be the ratio of  ΔGaΔGb?
  • 0
  • 1
  • between 01
  • >1
Which thermochemical process is shown by the following figure?

1843189_e066e32e2b8348f3a30c56ce6802fbe7.png
  • Standard enthalpy of a reaction
  • Born - Haber cycle of lattice enthalpy
  • Hess's law of constant heat summation
  • Standard enthalpy of a solution .
Read the following statements regarding the spontaneity of a process and mark the appropriate choice.
(i) When enthalpy factor is absent then randomness factor decides spontaneity of a process.
(ii) When randomness factor is absent then enthalpy factor decides spontaneity of a process.
(iii) When both the factors take place simultaneously the magnitude of both factors decides spontaneity of a process.
  • Statements (i) and (ii) are correct and (iii) is incorrect.
  • Statements (iii) and (i) are correct and (ii) is incorrect.
  • Statements (i), (ii) and (iii) are correct.
  • Statements (i), (ii) and (iii) are incorrect.
At dynamic equilibrium, the reactions on both sides occur at the same rate and the mass on both sides of the equilibrium does not undergo any change. This condition can be achieved only when the value of ΔG is: 
  • 1
  • +1
  • +2
  • 0
Which of the following conditions may lead to a non-spontaneous change?
  • ΔH and ΔS both +ve
  • ΔH=ve; ΔS=+ve
  • ΔH=+ve; ΔS=ve
  • ΔH=ve; ΔS=ve
Using the listed [ΔGof values] calculate ΔGo for the reaction:
3H2S(g)[33.6]+2HNO3(l)[80.6]2NO(g)[+86.6]+4H2O(l)[237.1]+3S(s)[0.0]
  • 513.0
  • 1037.0
  • +433.4
  • +225.0
Which of the following conditions will always lead to non-spontaneous change?
  • ΔH and ΔS both +ve
  • ΔH is -ve and ΔS is +ve
  • ΔH and ΔS both -ve
  • ΔH is +ve and ΔS is -ve
Which of the following options is/are correct?
  • [lnKpT]=ΔHoRT2
  • lnKT=EaRT2
  • [lnKpT]=ΔURT2
  • All of these
The free energy change ΔG=0, when
  • the system is at equilibrium
  • catalyst is added
  • reactants are initially mixed thoroughly
  • the reactants are completely consumed
The volume of a gas is reduced to half from its original volume. The specific heat will _____
  • be reduced to half
  • be doubled
  • remain constant
  • be increased four times
The heat required to raise the temperature of a body by 1 K is called :
  • specific heat
  • thermal capacity
  • water equivalent
  • molar heat capacity
Calculate the enthalpy of formation of I2O5(s) from the following data:
i) I2O5(s)+H2O(l)2HIO3(aq);      ΔH=+4.0kJ
ii) KI(aq)+3HClO(aq)HIO3(aq)+2HCl(aq)+KCl(aq);     ΔH=322.0kJ
iii) NaOH(aq)+HClO(aq)NaOCl(aq)+H2O(l) ;        ΔH=44.0kJ
iv) NaOH(aq)+HCl(aq)NaCl(aq)+H2O(l);    ΔH=57.0kJ
v) 2NaOH(aq)+Cl2(g)NaOCl(aq)+NaCl(aq)+H2O(l)ΔH=100.0kJ
vi) 2KI(aq)+Cl2(g)2KCl(aq)+I2(s);    ΔH=224.0kJ
vii) H2(g)+1/2O2(g)H2O(l);   ΔH=285.0kJ
viii) 1/2H2(g)+1/2Cl2(g)HCl(g); ΔH=92.0kJ
ix) HCl(g)+aqHCl(aq); ΔH=75.0kJ
  • 173.0kJ
  • +173.0kJ
  • +154.0kJ
  • 154.0kJ
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