CBSE Questions for Class 11 Medical Chemistry Thermodynamics Quiz 1 - MCQExams.com

A chemical reaction is spontaneous at 298 K but non-spontaneous at 350 K. Which one of the following is true for the reaction?
  • $$\Delta G\quad \Delta H\quad \Delta S\\ -\quad \quad -\quad \quad +$$
  • $$\Delta G\quad \Delta H\quad \Delta S\\ +\quad \quad +\quad \quad +$$
  • $$\Delta G\quad \Delta H\quad \Delta S\\ -\quad \quad +\quad \quad -$$
  • $$\Delta G\quad \Delta H\quad \Delta S\\ +\quad \quad -\quad \quad +$$
  • $$\Delta G\quad \Delta H\quad \Delta S\\ -\quad \quad -\quad \quad -$$
Which of the following statements regarding Gibb's energy change is correct?
  • If $$\Delta$$G is negative (< 0), the process is non-spontaneous.
  • If $$\Delta$$G is positive (> 0), the process is non-spontaneous.
  • If $$\Delta$$G is negative (< 0), the process is spontaneous.
  • If $$\Delta$$G is positive (> 0), the process is equilibrium.
$$\triangle H$$ = - 336.2 kcal. What is the value of $$\triangle U$$ approximately at 300 K for the same reaction (R = 2 cal $$degre{ e }^{ -1 }$$ $$mo{ l }^{ -1 }$$)?
1147334_1eb8e8d5b51e46e2b76d3352759e63f9.png
  • - 320.0 kcal
  • - 335.0 kcal
  • - 337.2 kcal
  • - 353.0 kcal
Properties of substances like pressure, temperature and density, in thermodynamic coordinates are 
  • path function
  • point function
  • cyclic function
  • real function
The INCORRECT match in the following is :
  • $$\Delta G^0 < 0,K< 1$$
  • $$\Delta G^0 < 0,K= 1$$
  • $$\Delta G^0 > 0,K< 1$$
  • $$\Delta G^0 < 0,K> 1$$
Which of the following property is not a thermodynamic property of the system?
  • pressure
  • temperature
  • specific volume
  • heat
Which heat depends on the direction of current?
  • Joule heat
  • Peltier heat
  • Thompson effect
  • None of these
An ideal gas undergoes a cyclic process as shown in Figure.

$$\Delta U_{BC}=-5$$ kJ $$mol^{-1}$$, $$q_{AB}=2$$ kJ $$mol^{-1}$$

$$W_{AB}=-5$$ kJ $$mol^{-1}$$, $$W_{CA}=3$$ kJ $$mol^{-1}$$

Heat absorbed by the system during process CA is:

868120_af609f5cc16d4673804cea4f5bff0cf1.png
  • $$+18$$ kJ $$mol^{-1}$$
  • $$-18$$ kJ $$mol^{-1}$$
  • $$-5$$ kJ $$mol^{-1}$$
  • $$+5$$ kJ $$mol^{-1}$$
The combustions of benzene (l) gives $$CO_2(g)$$ and $$H_2O(l)$$. Given that heat of combustion of benzene at constant volume is $$-3263.9 \ kJ\, mol^{-1}$$ at $$25^oC$$, heat of combustion (in $$kJ\,mol^{-1}$$) of benzene at constant pressure will be:
$$(R =8.314JK^{-1}\,mol^{-1})$$
  • $$+3260$$
  • $$-3267.6$$
  • $$+4152.6$$
  • $$-452.46$$
The standard Gibbs energy for the given cell reaction in $$kJ$$ $${mol}^{-1}$$ at $$298K$$ is:$$Zn(s)+{Cu}^{2+}(aq)\rightarrow {Zn}^{2+}(aq)+Cu(s)$$

$${E}^{o}_{cell}=2V$$ at $$298K$$
(Faraday's constant, $$F=96000\ C{mol}^{-1}$$)
  • $$-384$$
  • $$-192$$
  • $$192$$
  • $$384$$
A process will be spontaneous to all temperatures if:
  • $$\Delta H > 0$$ and $$\Delta S < 0$$
  • $$\Delta H < 0$$ and $$\Delta S > 0$$
  • $$\Delta H > 0$$ and $$\Delta S > 0$$
  • $$\Delta H < 0$$ and $$\Delta S < 0$$
Compute the heat of formation of liquid methyl alcohol (in kJ mol $$^{ -1 }$$) using the following data. The heat of vaporisation of liquid methyl alcohol is 38  kJ mol$$^{ -1 }$$. 

The heat of formation of gaseous atoms from the elements in their standard states: 
$$H =$$ 218  kJ mol$$^{ -1 }$$., $$C = 715$$  kJ mol$$^{ -1 }$$. , $$O = 249$$  kJ mol$$^{ -1 }$$.
 
Average bond energies:
$$C-H = 415$$  kJ mol$$^{ -1 }$$. 
$$C-O = 356$$ kJ mol$$^{ -1 }$$. 
$$O-H = 463$$  kJ mol$$^{ -1 }$$. 
  • $$\Delta H = -266$$ kJ mol$$^{ -1 }$$. 
  • $$\Delta H = +266$$ kJ mol$$^{ -1 }$$. 
  • $$\Delta H = -190$$ kJ mol$$^{ -1 }$$. 
  • None of these
For the process :

   $$\\ \mathrm{H}_{2}\mathrm{O}(l)$$ ($$1$$ bar, $$373$$ $$\mathrm{K}$$) $$\rightleftharpoons \mathrm{H}_{2}\mathrm{O}(\mathrm{g})$$ ( $$1$$ bar, $$373 \mathrm{K}$$),

the correct set of thermodynamic parameters is
  • $$\Delta \mathrm{G}=0,\Delta \mathrm{S}=+ ve$$
  • $$\Delta \mathrm{G}=0, \Delta S=-ve$$
  • $$\Delta \mathrm{G}=+ve, \Delta \mathrm{S}=0$$
  • $$\Delta \mathrm{G}=- ve, \Delta \mathrm{S}=+ ve$$
A gas mixture consists of $$2$$ moles of $$O_2$$ and $$4$$ moles of Ar at temperature $$T$$. Neglecting all vibrational modes, the total internal energy of the system is 
  • 11 RT
  • 4 RT
  • 15 RT
  • 9 RT
For a given reaction, $$\triangle H = 35.5\ kJmol^{-1}$$ and $$\triangle S = 83.6\ JK^{-1} mol^{-1}$$. The reaction is spontaneous at: (Assume that $$\triangle H$$ and $$\triangle S$$ do not vary with temperature)
  • $$T > 298\ K$$
  • $$T < 425\ K$$
  • $$T > 425\ K$$
  • All temperatures
The following two reactions are known 

$$Fe_2O_{3(s)} + 3CO_{(g)}\rightarrow 2Fe(s) + 3CO_{2(g)}$$ ; $$\Delta \ H = -26.8\ kJ$$

$$FeO_{(s)} + CO_{(g)}\rightarrow Fe_{(s)} + CO_{2(g)}\Delta H = -16.5\ kJ$$

The value of $$\Delta\ H$$ for the following reaction is:

$$Fe_2O_{3(s)} + CO_{(g)}\rightarrow 2FeO_{(s)} + CO_{2(g)}$$
  • + 10.3 kJ
  • - 43.3 kJ
  • - 10.3 kJ
  • + 6.2 kJ
Which of the following is the property of a system 
  • pressure and temperature
  • internal energy
  • volume and density
  • all of the above
Consider the following processes:
                                                  $$\Delta H\left({kJ}/{mol}\right)$$
$$\dfrac{1}{2} A \rightarrow B$$                               $$+150$$

$$3B \rightarrow 2C + D$$                       $$-125$$

$$E + A \rightarrow 2D$$                          $$+350$$

For $$B + D \rightarrow E + 2C,   \Delta H$$ will be:
  • $$525\ {kJ}/{mol}$$
  • $$-175\ {kJ}/{mol}$$
  • $$-325\ {kJ}/{mol}$$
  • $$325\ {kJ}/{mol}$$
One mole of an ideal diatomic gas undergoes a transition from A to B along a path AB as shown in the figure, The change in internal energy of the gas during the transition is:
333462.png
  • $$20\ J$$
  • $$-12\ kJ$$
  • $$20\ kJ$$
  • $$-20\ kJ$$
For the reaction, $$X_2O_4(i)\rightarrow 2XO_2(g)$$, $$\Delta U=2.1k cal, \Delta s=20 cal K^{-1}$$ at 300 K. 
Hence, $$\Delta G$$ is:
  • 2.7 k cal
  • -2.7 k cal
  • 9.3 k cal
  • -9.3 kcal
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Both Assertion and Reason are incorrect
The thermal motion means
  • motion due to heat engine
  • disorderly motion of the body as a whole
  • motion of the body that generates heat
  • random motion of molecules
Assertion (A) : Zeroth law of thermodynamics gives us the concept of energy
Reason (R) : Internal energy is dependent on temperature
  • 1) Both Assertion and Reason are true and reason is correct explanation of Assertion
  • 2) Both Assertion and Reason are true but reason is not correct explanation of Assertion
  • 3) Assertion is true but reason is false
  • 4) Assertion is false but reason is true
Internal energy per mole of gas depends on 
  • viscosity
  • density
  • temperature
  • thermal conductivity
The internal energy of an isolated system :
  • remains constant
  • keeps on changing
  • zero
  • may change depending on gas

The laws of thermodynamics speak about
  • rates of chemical changes
  • feasibility and energy transformations of a

    process
  • Both the rate and energy changes of a process
  • Energy changes in chemical reactions only
The internal energy of a perfect gas depends on :
  • Pressure
  • Temperature
  • Volume
  • Specific heat
The internal energy of an ideal gas depends upon 
  • only its pressure
  • only its volume
  • only its temperature
  • its pressure and volume

Internal energy does not include
  • vibrational energy
  • rotational energy
  • energy arising by gravitational pull
  • nuclear energy
Which of the following is not a thermodynamic coordinate?
  • Gas constant (R)
  • Pressure (P)
  • Volume (V)
  • Temperature (T)
Gas constant $$(R)$$ equals to
  • $$\dfrac{C_p}{C_v}$$
  • $$1$$
  • $$C_v-C_p$$
  • $$C_p-C_v$$
$$C_v$$ for ammonia gas is $$(in J \ mol^{-1} \ K^{-1})$$
  • $$29.0$$
  • $$12.5$$
  • $$20.7$$
  • $$31.2$$

The heat change in a chemical reaction at constant volume is given by:
  • $$\Delta H$$
  • $$\Delta E$$
  • $$\Delta T$$
  • $$\Delta V$$
At the boiling point of water the saturated vapour pressure will be (in mm of Hg)
  • 750
  • 760
  • 850
  • 860
$$10\ g$$ of liquid at $$300\ K$$ is heated to $$350\ K$$. The liquid absorbs $$6\ kcals$$. What is the specific heat of the liquid (in $$cal/g\ ^o C$$)?
  • $$6$$
  • $$12$$
  • $$60$$
  • $$120$$
Joule's experiment converts
  • work into heat
  • work into electricity
  • heat into work
  • electricity into work
What describes a spontaneous reaction?
  • Positive $$\Delta H$$
  • Negative $$\Delta H$$
  • Positive $$\Delta G$$
  • Negative $$\Delta G$$
The temperature at the bottom of a high water fall is higher than that at the top because
  • by itself heat flows from higher to lower temperature
  • the difference in height causes a difference in pressure
  • thermal energy is transformed into mechanical energy
  • mechanical energy is transformed into thermal energy
Therm is the unit of
  • heat
  • temperature
  • thermometry
  • work
Combustion is
  • exothermic reaction
  • endothermic reaction
  • addition reaction
  • None of these
Which one of the following is not a thermodynamical co-ordinate?
  • $$V$$
  • $$R$$
  • $$T$$
  • $$P$$
Fill in the blank. 
Thermodynamics is the branch of science concerned with ____ and ________ and their relation to energy and work. 
  • heat, temperature
  • temperature, pressure
  • heat, volume
  • volume, pressure
Identify the incorrect statement ?
  • Energy can be converted into matter
  • Matter can be converted into energy
  • Energy can be converted into matter, and matter can be converted into energy
  • Matter can be converted into energy, but energy cannot be converted into matter
  • Energy can be measured in units of joules and calories
If there were no atmosphere, the average temperature on earth surface would be
  • lower
  • higher
  • same
  • $${{0}^{o}}C$$
Mixture of ice and water is form a 
  • closed system
  • open system
  • isolated system
  • heterogeneous system
Free energy change for the process $$A(s)\rightleftharpoons B(l)$$ will be:
  • 0
  • 1
  • 2
  • 3
$$ \Delta U^{ \ominus  } $$ of combustion of methane is $$ -X kJ mol^{-1} $$ The value of $$ \Delta H^{ \ominus  } $$ is 
  • $$ = \Delta U^{ \ominus } $$
  • $$ > \Delta U^{ \ominus } $$
  • $$ < \Delta U^{ \ominus } $$
  • $$ 0 $$
The internal energy of compressed real gas, as  compared to that of the ideal gas at the same temperature is
  • less
  • more
  • sometimes less, sometimes more
  • maximum
The internal energy of a perfect gas is :
  • completely kinetic
  • completely potential
  • sum of potential and kinetic energy of the molecules
  • difference of kinetic and potential energy of the molecules
Which of the following process is non-spontaneous?
  • Heat flow from hot end to cool end.
  • Water flow from higher level to lower level.
  • Gas flow from lower pressure region to higher pressure region.
  • Gas flow from higher pressure region to lower pressure region.
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