CBSE Questions for Class 11 Medical Chemistry Thermodynamics Quiz 10 - MCQExams.com

Heat of reaction for the reaction is:

$$PCl_5(g)+H_2O(g)\longrightarrow POCl_3(g)+2HCl(g)$$

Given that,
$$P_{white} + (3/2)Cl_2(g) +\frac{1}{2}O_2(g)\longrightarrow POCl_3; \:  \Delta H=-135.5 \:kcal$$
   
$$H_2( g ) + Cl_2( g )\longrightarrow +2HCl(g); \:                       \Delta H=-44.1 \:kcal$$

$$P(w)+(5/2)Cl_2(g)\longrightarrow PCl_5(g); \:                                \Delta H=-89.6 \:kcal$$
 
 $$H_2(g)+\frac{1}{2}O_2(g)\longrightarrow H_2O(g);\:                          \Delta H=-57.8\:kcal$$
  • $$-32.2 kcal$$
  • $$-52.5 kcal$$
  • $$-45.2 kcal$$
  • None of these
The dissolution of 1 mole of NaOH(s) in $$100 \: mole \: of \: H_2O(l)$$ give rise to evolution of heat as -42.34 kJ. However, if1 mole of NaOH(s) is dissolved in $$1000 \:mole \:of \:H_2O(l)$$ the heat given out is 42.76 kJ. 

If the enthalpy change when $$900 \:mole \:of \:H_2O(l) $$ are added to a solution containing 1 mole of NaOH(s) in $$100 \:mole \:of \:H_2O$$ is $$x$$ $$kJ$$:
  • $$-0.42$$
  • $$0.42$$
  • $$0.24$$
  • None of these
The heat measured for a reaction in bomb calorimeter is :
  • $$\Delta G$$
  • $$\Delta H$$
  • $$\Delta U$$
  • $$P\Delta V$$
1 gram sample of $$NH_4NO_3$$ is decomposed in a bomb calorimeter. The temperature of the calorimeter increases by 6.12 K. The heat capacity of the system is 1.23 kJ/g-deg. What is the molar heat of decomposition for $$NH_4NO_3$$?
  • -7.53 kJ/mol
  • -398.1 kJ/mol
  • -16.1 kJ/mol
  • 602 kJ/mol
The $$\Delta_f H^{\circ}$$ for $$CO_2 (g), \: CO(g) \: and \: H_2O(g)$$ are $$-393.5, -110.5$$ and $$-241.8 \: kJ \: mol^{-1}$$ respectively. The standard enthalpy change (in kJ) for the reaction is:

$$CO_2 (g)+ H_2 (g)\longrightarrow CO(g)+ H_2O(g )$$ 
  • 524.1
  • 41.2
  • -262.5
  • -41.2
Combustion of carbon studies in a bomb calorimeter to obtain heat of reaction. Which of the following options are correct?
  • The value obtained shows change in heat enthalpy.
  • The value obtained shows change in internal energy.
  • The volume remains constant.
  • The pressure remains constant.
The commercial production of water gas utilize the reaction under standard conditions:

                           $$C+H_2O(g)\longrightarrow  H_2(g)+CO$$

The heat required for this endothermic reaction may be supplied by adding a limited amount of air and burning some carbon to $$CO_2$$. How many g of carbon must be burnt to $$CO_2$$ to provide enough heat for the water-gas conversion of 100 g carbon? 

Neglect all heat losses to the environment. Also $$\Delta _fH^{\circ}$$ of CO, $$H_2O(g)$$ and $$CO_2$$ are -110.53, 241.81 and -393.51 kJ/mol respectively.
  • $$33.4 g$$
  • $$66.72 g$$
  • $$15.18 g$$
  • None of these
The enthalpies of formation of $$N_2O$$ and $$NO$$ are $$28$$ and $$90\ kJ mol^{-1}$$ respectively. The enthalpy of the reaction, $$2N_2O(g) +O_2(g)\longrightarrow 4NO(g)$$ is equal to :
  • 8 kJ
  • 88 kJ
  • -16 kJ
  • 304 kJ
Select the incorrect statements:
  • A few combustion process are endothermic
  • Heat of combustion may be positive
  • Exothermic compounds arc more stable than endothermic compounds
  • Hess's law can he verified experimentally
Which of the following are applicable for a thermochemical equations? It tells:
  • about the physical state of reactants and products.
  • about the allotropic form (if any) of the reactants.
  • whether the reaction is exothermic or endothermic.
  • whether a particular reaction is spontaneous or not.
Which of the following are correct for the given diagram?


217226.jpg
  • $$\Delta H_3=\Delta H_1+\Delta H_2$$
  • $$\Delta H_1=0$$
  • $$\Delta H_2 = (C_{calorimeter}+ C_{product})\times (T_1-T_2)$$
  • $$\Delta H_2 = (C_{calorimeter}+ C_{product})\times (T_2-T_1)$$
Find the $$\Delta H$$ of the following reaction. $$OF_2(g) + H_2O(g)\longrightarrow O_2(g) + 2HF(g)$$. Average bond energies of $$O-F$$, $$O-H$$, $$O=O$$ and $$H-F$$ are $$44$$, $$111$$, $$118$$ and $$135 $$ kcal mol$$^{ -1 }$$, respectively.
  • $$\Delta H= -78\ kcal$$
  • $$\Delta H= +78\ kcal$$
  • $$\Delta H= -498\ kcal$$
  • $$\Delta H= +498 \ kcal$$
The thermo-chemical equation for solid and liquid rocket fuel are given below:
$$2Al(s) + 1\frac { 1 }{ 2 }O_2(g)\longrightarrow Al_2O_3(s), \Delta H = -1667.8 kJ$$

$$H_2(g) +\frac { 1 }{ 2 }O_2(g)\longrightarrow H_2O(l), \Delta H = -285.9 kJ$$, 

Then, $$\Delta H$$ for the reaction : $$Al_2O_3(s)\longrightarrow 2Al(s) + 1\frac { 1 }{ 2 }O_2(g)$$ is :
  • $$\ 1667.8\ kJ mol^{ -1 }$$
  • $$\ 1222.3\ kJ mol^{ -1 }$$
  • $$\ 1458.2\ kJ mol^{ -1 }$$
  • $$\ 1785.3\ kJ mol^{ -1 }$$
Which of the following has the same value as $$\Delta_f H^{ \ominus }$$ , $$CO$$
a. $$\frac { 1 }{ 2 } \Delta_f H^{ \ominus } (CO_2)$$
b. $$\frac { 1 }{ 2 } \Delta_c H^{ \ominus } (graphite)$$
c. $$\Delta_f H^{ \ominus } (CO_2) - \Delta_f H^{ \ominus } (graphite)$$
d. $$\Delta_c H^{ \ominus } (graphite) - \Delta _c H^{ \ominus } (CO)?$$
  • a
  • b
  • c
  • d
If  the resonance energy of $$NO_2(:O--N==O:)$$ is X kJ The measured enthalpy formation of $$NO_2(\Delta_f H^{ \ominus } )$$ is $$34  kJ  mol^{ -1 }$$. The bond energies given are:
$$N--O \Rightarrow 222  kJ  mol^{ -1 }$$
$$N\equiv N \Rightarrow 946  kJ  mol^{ -1 }$$
$$O==O \Rightarrow 498  kJ  mol^{ -1 }$$
$$N==O \Rightarrow 607  kJ  mol^{ -1 }$$
Find out the value of X
  • $$X= -108 $$
  • $$X= +108 $$
  • $$X= -59$$
  • None of these
A change in the free energy of a system at constant temperature and pressure will be:

$$\Delta_{ sys }G = \Delta_{ sys }H - T\Delta_{ sys }S$$

At constant temperature and pressure,
$$\Delta_{ sys }G < 0 (spontaneous)$$
$$\Delta_{ sys }G = 0 (equilibrium)$$
$$\Delta_{ sys }G > 0 (non-spontaneous)$$

For a system in equilibrium, $$\Delta G = 0$$, under conditions of constant_____
  • temperature and pressure
  • pressure and volume
  • temperature and volume
  • energy and volume
Calculate the $$\Delta H^{ \ominus }$$ for the reduction of $$Fe_2O_3(s)$$ by $$Al(s)$$ at $$25^{ \circ }C$$. The enthalpies of formation of $$Fe_2O_3(s)$$ and $$Al_2O_3$$ are $$-825.5$$ and $$-1675.7  kJ  mol^{ -1 }$$ respectively.
  • $$\Delta H= - 850.2 kJ mol^{ -1 }$$
  • $$\Delta H= +850.2 kJ mol^{ -1 }$$
  • $$\Delta H= - 2500 kJ mol^{ -1 }$$
  • None of these
4 grams of sodium hydroxide pellets were dissolved in $$100  {cm}^{3}$$ of water. The temperature before adding the sodium hydroxide pellets was 25 degrees C, and after adding the pellets it was 35 degrees C. Calculate the enthalpy change in $${kJ}/{mole}$$ of the reaction.
[Specific heat capacity of water $$= 4.2  {J}/{k}/{g}]$$
  • $$42 {kJ}/{mole}$$
  • $$4.2 {kJ}/{mole}$$
  • $$4200 {kJ}/{mole}$$
  • None
How much heat is liberated when one mole of gaseous $$Na^{ \oplus }$$ combines with one mole of $$Cl^{ \ominus }$$ ion to form solid $$NaCl$$.

Use the data given below:
$$Na(s) + \frac { 1 }{ 2 } Cl_2(g) \longrightarrow NaCl(s)$$;       $$\Delta H = -98.23  kcal$$ 
$$Na(s)\longrightarrow Na(g)$$;$$\,\,\,\, \Delta H = +25.98  kcal$$
$$Na(g)\longrightarrow Na^{ \oplus } + e^ { - }$$;$$\,\,\,\,\,\,\,\Delta H = +120.0  kcal$$
$$Cl_2(g)\longrightarrow 2Cl(g)$$;$$\,\,\,\,\,\,\,\,\Delta H = +58.02  kcal$$
$$Cl^{ \ominus } (g)\longrightarrow Cl(g) + e^{ - }$$;$$\,\,\,\,\,\,\,\Delta H = +87.3  kcal$$
  • $$\Delta H = -185.92 Kcal$$
  • $$\Delta H = +185.92 Kcal$$
  • $$\Delta H = 0 Kcal$$
  • None of these
$$\Delta_f H^{ \ominus }$$ of Cyclohexene $$(l)$$ and benzene at $$25^{ \circ}C$$ is $$-156$$ and $$+46  kJ  mol^{ -1 }$$, respectively. 
$$\Delta_{ hydrogenation }H^{ \ominus }$$ of Cyclohexene $$(l)$$ at $$25^{ \circ }C$$ is $$-119  kJ  mol^{ -1 }$$.

Resonance energy of benzene is found to be $$-38x  kJ  mol^{ -1 }$$. Find the value of x.
  • 4
  • 2
  • 8
  • None of these
If $$2Al(s) + 1\frac { 1 }{ 2 }O_2(g)\longrightarrow Al_2O_3(s), \Delta H = -166.78 kJ$$
$$H_2(g) + \frac { 1 }{ 2 }O_2(g)\longrightarrow H_2O(l), \Delta H = -285.9 kJ$$

Then  $$\Delta H$$ for the reaction,

$$Al_2O_3(s)\longrightarrow 2Al(s) + 1\frac { 1 }{ 2 }O_2(g)$$ is:
  • $$\Delta H = 174.20kJ mol^{ -1 }$$
  • $$\Delta H = 124.55 kJ mol^{ -1 }$$
  • $$\Delta H = 166.78 kJ mol^{ -1 }$$
  • $$\Delta H = 156.33 kJ mol^{ -1 }$$
Determine $${ \Delta H }/{ kJ }$$ for the following reaction using the listed enthalpies of reaction:
$$4CO\left( g \right) +8{ H }_{ 2 }\left( g \right) \longrightarrow 3C{ H }_{ 4 }\left( g \right) +C{ O }_{ 2 }\left( g \right) +2{ H }_{ 2 }O\left( l \right) $$

$$C\left( graphite \right) +{ 1 }/{ 2 }{ O }_{ 2 }\left( g \right) \longrightarrow CO\left( g \right) ;                           { \Delta H }/{ kJ }=-110.5kJ$$

$$CO\left( g \right) +{ 1 }/{ 2 }{ O }_{ 2 }\left( g \right) \longrightarrow C{ O }_{ 2 }\left( g \right)         ;                 { \Delta H }/{ kJ }=-282.9kJ$$

$${ H }_{ 2 }\left( g \right) +{ 1 }/{ 2 }{ O }_{ 2 }\left( g \right) \longrightarrow { H }_{ 2 }O\left( l \right)        ;                   { \Delta H }/{ kJ }=-285.8kJ$$

$$C\left( graphite \right) +2{ H }_{ 2 }\left( g \right) \longrightarrow C{ H }_{ 4 }\left( g \right)           ;                       { \Delta H }/{ kJ }=-74.8kJ$$
  • -622.4
  • -686.2
  • -747.5
  • -653.5
$$\Delta_f H^{ \ominus }$$ of hypothetical $$MgCl$$ is $$-125  kJ  mol^{ -1 }$$ and for $$MgCl_2$$ is $$-642  kJ  mol^{ -1 }$$. The enthalpy of disproportionation of $$MgCl$$ is $$-49x$$. Find the value of x.
  • $$x = 8$$
  • $$x = 8.5$$
  • $$x = 16$$
  • None of these
Using the enthalpies of formation, calculate the energy (kJ) released when $$3.00  g$$ of $$N{ H }_{ 3\left( g \right)  }$$ reacts according to the following equation?
(Atomic weights: $$N = 14.00,  H = 1.008$$).
          $$4N{ H }_{ 3 }\left( g \right) +5{ O }_{ 2 }\left( g \right) \longrightarrow 4NO\left( g \right) +6{ H }_{ 2 }O\left( g \right) $$
$$\Delta HN{ H }_{ 3 }\left( g \right) =-46.1   { kJ }/{ mole }$$
$$\Delta HNO\left( g \right) =+90.2   { kJ }/{ mole }$$
$$\Delta H{ H }_{ 2 }O\left( g \right) =-241.8   { kJ }/{ mole }$$
  • $$34.3$$
  • $$30.8$$
  • $$39.9$$
  • $$42.6$$
Calculate $${ \Delta H }/{ kJ }$$ for the following reaction using the listed standard enthalpy of reaction data.
$$2{ N }_{ 2 }\left( g \right) +5{ O }_{ 2 }\left( g \right) \longrightarrow 2{ N }_{ 2 }{ O }_{ 5 }\left( s \right) $$

$${ N }_{ 2 }\left( g \right) +3{ O }_{ 2 }\left( g \right) +{ H }_{ 2 }\left( g \right) \longrightarrow 2HN{ O }_{ 3 }\left( aq \right)    ;        \           { \Delta H }/{ kJ }=-414.0$$

$${ N }_{ 2 }{ O }_{ 5 }\left( s \right) +{ H }_{ 2 }O\left( l \right) \longrightarrow 2HN{ O }_{ 3 }\left( aq \right)                  ;    \       { \Delta H }/{ kJ }=-86.0$$

$$2{ H }_{ 2 }\left( g \right) +{ O }_{ 2 }\left( g \right) \longrightarrow 2{ H }_{ 2 }O\left( l \right)                     ;      \    { \Delta H }/{ kJ }=-571.6$$
  • -84.4
  • -243.6
  • -71.2
  • -121.8
Calculate the value of $${ \Delta H }{\ ( kJ) }$$ for the following reaction using the listed thermochemical equations $$2C(s) + H_2(g) \rightarrow C_2H_ 2 (g)$$.

$$2{ C }_{ 2 }{ H }_{ 2 }\left( g \right) +5{ O }_{ 2 }\left( g \right) \longrightarrow 4C{ O }_{ 2 }\left( g \right) +2{ H }_{ 2 }O\left( l \right)$$ ;     $$\Delta H^o= -2600\ kJ$$
$$C\left( s \right) +{ O }_{ 2 }\left( g \right) \longrightarrow C{ O }_{ 2 }\left( g \right)$$ ;                                      $$\Delta H^o=-390\ kJ$$
$$2{ H }_{ 2 }\left( g \right) +{ O }_{ 2 }\left( g \right) \longrightarrow 2{ H }_{ 2 }O\left( l \right)$$ ;                                $$\Delta H^o =-572\ kJ$$
  • $$+184$$
  • $$+214$$
  • $$+202$$
  • $$+234$$
Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction:
         $${ C }_{ 2 }{ H }_{ 5 }OH\left( l\right) +3{ O }_{ 2 }\left( g \right) \longrightarrow 2C{ O }_{ 2 }\left( g \right) +3{ H }_{ 2 }O\left( g \right) $$
$$\Delta { H }_{ f }^{ }{ C }_{ 2 }{ H }_{ 5 }OH\left( l \right) =-277.7{ kJ }/{ mole }$$
$$\Delta { H }_{ f }^{ }C{ O }_{ 2 }\left( g \right) =-393.5{ kJ }/{ mole }$$
$$\Delta { H }_{ f }^{ }{ H }_{ 2 }O\left( g \right) =-241.8{ kJ }/{ mole }$$
  • -1456.3
  • -1234.7
  • -1034.0
  • -1119.4
The enthalpy change for the following process at $${25}^{o}C$$ and under constant pressure at $$1$$ atm are as follows:
$${CH}_{4}(g)\longrightarrow C(g)+4H(g)$$ $${\Delta}_{r}H=396kcal/mole$$
$${C}_{2}{H}_{6}(g)\longrightarrow 2C(g)+6H(g)$$ $${\Delta}_{r}H=676kcal/mole$$

Calculate $$C-C$$ bond energy in $${C}_{2}{H}_{6}$$ and heat formation of $${C}_{2}{H}_{6}(g)$$.

[Given: $${\Delta}_{sub}C(s)=171.8kcal/mole$$   $$B.E(H-H)=104.1kcal/mole$$]
  • $$B.E(C-C)=82kcal/mol, {\Delta}_{f}H[{C}_{2}{H}_{6}(g)]=-20.1kcal/mol$$
  • $$B.E(C-C)=-82kcal/mol, {\Delta}_{f}H[{C}_{2}{H}_{6}(g)]=-20.1kcal/mol$$
  • $$B.E(C-C)=82kcal/mol, {\Delta}_{f}H[{C}_{2}{H}_{6}(g)]=+20.1kcal/mol$$
  • None of these
Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction:
               $$2LiOH+C{ O }_{ 2 }\left( g \right) \longrightarrow { Li }_{ 2 }C{ O }_{ 3 }\left( s \right) +{ H }_{ 2 }O\ (l)$$
$$\Delta { H }_{ f }^{ }LiOH\left( s \right) =-487.23{ kJ }/{ mole }$$
$$\Delta { H }_{ f }^{ }{ Li }_{ 2 }C{ O }_{ 3 }\left( s \right) =-1215.6{ kJ }/{ mole }$$
$$\Delta { H }_{ f }^{ }{ H }_{ 2 }O\ (l) =-285.85{ kJ }/{ mole }$$
$$\Delta { H }_{ f }^{ }C{ O }_{ 2 }\left( g \right) =-393.5{ kJ }/{ mole }$$
  • $$+303.4$$
  • $$-133.5$$
  • $$-198.6$$
  • $$+198.6$$
Determine $$\Delta H$$ of the following reaction using the listed heats of formation:
               $$4HN{ O }_{ 3 }\left( I \right) +{ P }_{ 4 }{ O }_{ 10 }\left( s \right) \longrightarrow 2{ N }_{ 2 }{ O }_{ 5 }\left( s \right) +4HP{ O }_{ 3 }\left( s \right) $$
$$\Delta { H }_{ f }^{ }HN{ O }_{ 3 }\left( I \right) =-174.1{ kJ }/{ mole }$$
$$\Delta { H }_{ f }^{ }{ N }_{ 2 }{ O }_{ 5 }\left( s \right) =-43.1{ kJ }/{ mole }$$
$$\Delta { H }_{ f }^{ }{ P }_{ 4 }{ O }_{ 10 }\left( s \right) =-2984.0{ kJ }/{ mole }$$
$$\Delta { H }_{ f }^{ }HP{ O }_{ 3 }\left( s \right) =-948.5{ kJ }/mole$$
  • -176.3
  • -199.8
  • +276.2
  • -242.4
Caesium chloride is formed according to the following equation:

$$Cs(s)+0.5{Cl}_{2}(g)\longrightarrow CsCl(s)$$

The enthalpy of sublimation of $$Cs$$, enthalpy of dissociation of chlorine, ionization energy of $$Cs$$ and electron affinity of chlorine are $$81.2, 243.0, 375.7$$ and $$-348.3kJ$$ $${ol}^{-1}$$. The energy change involved in the formation of $$CsCl$$ is $$388.6\ kJ.{mol}^{-1}$$. Calculate the lattice energy of $$CsCl$$.
  • $$-618.7\ kJ{mol}^{-1}$$
  • $$+618.7\ kJ{mol}^{-1}$$
  • $$1315.2\ kJ{mol}^{-1}$$
  • None of these
Determine $${ \Delta H }/{ kJ }$$ for the following reaction using the listed enthalpies of reaction:
$$4CO\left( g \right) +8{ H }_{ 2 }\left( g \right) \longrightarrow 3C{ H }_{ 4 }\left( g \right) +C{ O }_{ 2 }\left( g \right) +2{ H }_{ 2 }O\left( l \right) $$

Given that
$$C\left( graphite \right) +{ 1 }/{ 2 }{ O }_{ 2 }\left( g \right) \longrightarrow CO\left( g \right)    ;        \                { \Delta H }/{ kJ }=-110.5kJ$$

$$CO\left( g \right) +{ 1 }/{ 2 }{ O }_{ 2 }\left( g \right) \longrightarrow C{ O }_{ 2 }\left( g \right)      ;\                    { \Delta H }/{ kJ }=-282.9kJ$$

$${ H }_{ 2 }\left( g \right) +{ 1 }/{ 2 }{ O }_{ 2 }\left( g \right) \longrightarrow { H }_{ 2 }O\left( l \right)     ;\                      { \Delta H }/{ kJ }=-285.8kJ$$

$$C\left( graphite \right) +2{ H }_{ 2 }\left( g \right) \longrightarrow C{ H }_{ 4 }\left( g \right)       ;\                           { \Delta H }/{ kJ }=-74.8kJ$$
  • $$584.9\:kJ\:mol^{-1}$$
  • $$279.8\:kJ\:mol^{-1}$$
  • $$747.4\:kJ\:mol^{-1}$$
  • $$925\:kJ\:mol^{-1}$$
Using the data (all values are in $$kJ/mol$$ at $${25}^{o}C$$) given below:

(i) Enthalpy of polymerization of ethylene$$=-72$$
(ii) Enthalpy of formation of benzene $$(l)=49$$
(iii) Enthalpy of vaporization of benzene $$(l)=30$$
(iv) Resonance energy of benzene $$(l)=-152$$
(v) Heat of formation of gaseous atoms from the elements in their standard states $$H=218, C=715$$.

Average bond energy of $$C-H=415$$. Calculate the $$B.E$$ of $$C-C$$ and $$C=C$$.
  • $$C-C=343.67$$, $$C=C=615.33$$
  • $$C-C=615.33$$, $$C=C=342.67$$
  • $$C-C=343.67$$, $$C=C=959$$
  • None of these
Use the given standard enthalpies of formation to determine the heat of reaction of the following reaction:  $$TiCL_4(g)+2\:H_2O(g)\rightarrow TiO_2(g)+4\:HCl(g)$$

$$\Delta H^{\circ}_f\:TiCL_4(g)=-763.2\:kJ/mol$$
$$\Delta H^{\circ}_f\:TiO_2(g)=-944.7\:kJ/mol$$
$$\Delta H^{\circ}_f\:H_2O(g)=-241.8\:kJ/mol$$
$$\Delta H^{\circ}_f\:HCl(g)=-92.3\:kJ/mol$$
  • $$-\:278.1$$
  • $$+\:369.2$$
  • $$+\:67.1$$
  • $$-\:67.1$$
How many joules of heat are absorbed when 70.0 g of water is completely vaporised at its boiling point ?
[Take : LV = 2260 kJ / kg]
  • 22352
  • 52460
  • 22344
  • 158200
Anhydrous $$AlCl_3$$ is a covalent compound. From the data given below, predict whether it would remain covalent or become ionic in an aqueous solution .

Ionisation energy of $$Al = 5137 \ kJ mol^{-1}$$, $$\Delta H$$ hydration for $$Al^{3+}=-4665\:kJ\:mol^{-1};$$ $$\Delta H$$ hydration for $$Cl^-=-381\:kJ\:mol^{-1}$$
  • Ionic
  • Covalent
  • Partially ionic
  • Partially covalent
A piston filled with 0.04 mole of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 37.0°C. As it does so, it absorbs 207 J of heat. The values of q and W for the process will be :
[Take : R = 8.314 J / mol K, In 7.5 = 2.01]
  • q = +207, W = -207
  • q = -207, W = -207
  • q = -207, W = +207
  • q = +207, W = +207
A swimmer coming out from a pool is covered with a film of water weighing about 18 g. Calculate the internal energy of vaporisation at 100°C.
[$$\Delta H_{vap}^o$$ for water at 373 K = 40.66 kJ/mol ]

The correct option is:
  • 35.67 kJ
  • 36.64 kJ
  • 37.56 kJ
  • None of the above
The enthalpies of formation of $$Al_2O_3$$ and $$Cr_2O_3$$ are -1596 kJ and -1134 kJ respectively. $$\Delta H$$ for the reaction,
$$2Al + Cr_2O_3\rightarrow 2Cr + Al_2O_3$$ is :
  • -2730 kJ
  • -462 kJ
  • -1365 kJ
  • +2730 kJ
According to the given reaction, when a $$45 $$ gram sample of the ethanol is burned with excess oxygen, how much energy is released in the form of heat?

$$C_2H_5OH(l) + 3O_2(g)\rightarrow 2CO_2(g) + 3H_2O(l)$$

$$\triangle H = -1.40\times 10^3$$ kJ.
  • 0.995 kJ
  • $$5.1 \times 10^2 $$ kJ
  • $$1.40 \times 10^3$$ kJ
  • $$2.80 \times 10^3$$  kJ
  • 5000 kJ
If 10 g of liquid at 300K is heated to 350 K, the liquid absorbs 6 kcals. Determine the specific heat of the liquid in cal/$$\displaystyle { g }^{ \circ  }C$$.
  • 6
  • 12
  • 60
  • 120
  • 600
Compute $$\Delta_rG$$ for the reaction $$H_2O (;, 1 atm, 323 K) \rightarrow H_2O (g, 1 atm, 323 K)$$
Given that : $$\Delta_{vap}H$$ at $$373 K = 40.639 kJmol^{1}, C_P(H_2O, l) = 75.312 J K^{1} mol^{1},
C_P(H_2O, g) = 33.305 J K^{1}mol^{1}$$
  • $$\Delta_rG = 5.59 kJ mol^{1}$$
  • $$\Delta_rG = -5.59 kJ mol^{1}$$
  • $$\Delta_rG = 55.9 kJ mol^{1}$$
  • None of these
Calculate the $${ \Delta H }_{ r }$$ of KH(s).
  • 62 kJ/mol
  • 124 kJ/mol
  • 31 kJ/mol
  • None of these
Fixed amount of an ideal gas contained in a sealed rigid vessel $$(V = 24.6\ litre)$$ at $$1.0$$ bar is heated reversibly from $$27^oC$$ to $$127^oC$$. 
Determine change in Gibb's energy (in Joule) if entropy of gas $$S = 10 + 10^{2} T (J/K)$$.
  • $$-530$$ J
  • $$+530$$ J
  • $$530$$ kJ
  • None of the above
Calculate the free energy change at $$298 K$$ for the reaction :
$$Br_2(l) + Cl_2(g) \rightarrow 2BrCl(g)$$. For the reaction $$\Delta H^o = 29.3 kJ$$ & the entropies of 
$$Br_2(l), Cl_2(g)$$ & BrCl(g) at the $$298 K$$ are $$152.3, 223.0, 239.7$$ $$J mol^{1} K^{1} $$ respectively
  • $$1721.8 J$$
  • $$1721.8 kJ$$
  • $$17218 J$$
  • None of these
What is internal energy change of combustion for methanol?
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  • $$-680\:kJ/mole$$
  • $$-6.8\:kJ/mole$$
  • $$-567\:kJ/mole$$
  • $$-5.67\:kJ/mole$$
For the reaction $$X_2O_4(l)\rightarrow 2XO_2(g)$$, $$\Delta U = 2.1\,Kcal,$$ and $$\Delta S = 20\,cal\,K^{ -1 }$$ at 300 K. Hence, $$\Delta G$$ is:
  • $$2.7\,Kcal$$
  • $$-2.7\,Kcal$$
  • $$9.3\,Kcal$$
  • $$-9.3\,Kcal$$
The energy of a system available to do work is called as:
  • gibbs free energy
  • heat of formation
  • specific heat
  • heinsenberg uncertainty principle
  • heat of vaporization
What is the amount of the heat necessary to raise the temperature of $$50.0$$ grams of liquid water from $$10.0 ^{\circ} C$$ to $$30.0  ^{\circ}C$$.
(The specific heat of water liquid is $$4.18\ J/g/ ^{\circ}C$$)
  • $$20\ J$$
  • $$80\ J$$
  • $$100\ J$$
  • $$200\ J$$
  • $$4,180\ J$$
A certain amount of potassium chlorate on thermal decomposition gives oxygen which is sufficient for the combustion of ethane. When the products are cooled, the volume of the gaseous product is v ml. Identify the correct sequence of steps for the calculation of the mass of potassium chlorate
(a) Calculation of oxygen required for the combustion of ethane.
(b) Calculation of the amount of the ethane subjected to combustion from the volume of gaseous product.
(c) Calculation of potassium chlorate which can give the required amount of oxygen.
(d) Identification of the products of combustion of ethane and the product left after the cooling of products.
  • a b c d
  • d b a c
  • b c a d
  • d a c b
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Practice Class 11 Medical Chemistry Quiz Questions and Answers