CBSE Questions for Class 11 Medical Chemistry Thermodynamics Quiz 2 - MCQExams.com

Energy hidden in a definite quantity of substance is:
  • Enthalpy
  • Internal energy
  • Free energy
  • Entropy

Hess's law of constant heat summation is based on
  • E = mc$$^{2}$$
  • conservation of mass
  • first law of thermodynamics
  • E = h$$\nu $$

Regarding a thermochemical equation, wrong statement is
  • It tells about the physical states of reactants and products
  • It tells whether the reaction is exothermic or endothermic
  • It tells about the allotropic form (if any) of the reactant
  • It tells whether the reaction is possible or not

All natural processes are:
  • Spontaneous
  • Non- spontaneous
  • Exothermic
  • Endothermic

The heat change associated with reactions at constant volume is due to the difference in which property of the reactants and the products ?
  • internal energy
  • enthalpy
  • heat capacity
  • free energy

Hess’s law deals with:
  • heat changes in a chemical reaction.
  • rate of reaction
  • equilibrium constant
  • influence of pressure on volume of a gas
Which type of molecular motion does contribute towards internal energy for an ideal mono-atomic gas? 
  • Translational
  • Rotational
  • Vibrational
  • All of the above
One mole of a monoatomic gas is heated at a constant pressure of $$1atm$$ from $$0K$$ to $$100K$$. If the gas constant $$R=8.32J{mol}^{-1}{K}^{-1}$$, the change in the internal energy of the gas is approximately
  • $$2.3J$$
  • $$46J$$
  • $$8.67\times{10}^{3}J$$
  • $$1.25\times{10}^{3}J$$

When a solid melts, there is

i) increase in enthalpy

ii) decrease in internal energy

iii) decrease in enthalpy
  • all are correct
  • i only correct
  • ii only correct
  • iii only correct

What is the free energy change, $$'\Delta G'$$ When 1.0 mole of water at 100$$^{0}$$C and 1atm pressure is converted into steam at 100$$^{0}$$C and 1atm pressure
  • 540 cal
  • -9800 cal
  • 9800 cal
  • 0 cal
$$\Delta H_{f}=$$ -98.2 K.Cal/mole
$$S_{Na} =$$ 36 K.Cal/mole
$$I_{Na} =$$ 118.5 K.Cal/mole
$$\dfrac{1}{2}D_{Cl_{2}}=$$ 29 K.Cal/mole
$$U_{NaCl}=$$ -184.2 K.Cal/mole
From the data given below for $$NaCl$$, the electron affinity of chlorine $$[-E_{a}]$$ is:
  • -97.5 K.cal/ mole
  • -108 K.cal/mole
  • -75 K.cal/mole
  • -128 K.cal/mole
Born - Haber cycle may be used
  • to find out electron affinity of non-metal atoms
  • to find out lattice energy of the ionic compounds
  • for the preparation of ammonia in industries
  • both A and B

Which of the following relations is not correct?
  • $$G=H-TS$$
  • $$\Delta G_{system} = \Delta H _{system} T \Delta S_{system}$$
  • $$T \Delta S_{system} = \Delta H_{system} -\Delta G_{system}$$
  • $$\Delta H_{system} =\Delta G _{system} + T\Delta S_{system}$$

Gibbs energy change $$\Delta $$G is related to equilibrium constant K as:
  • $$\Delta G^{0}$$ = $$- RT lnk$$
  • $$\Delta G^{0}$$ = $$RT lnk$$
  • $$lnk$$ = $$-\frac{RT}{\Delta G^{0}}$$
  • $$lnk$$ = $$\frac{\Delta G^{0}}{RT}$$

Which of the following relation is incorrect?
  • $$\Delta S=\Delta H$$  + $$T\Delta G$$
  • $$\Delta S=\frac{\Delta H-\Delta G}{T }$$
  • $$– \Delta G = - W_{non\ exp.}$$
  • $$W_{PV} = –P \Delta  V$$

In a chemical reaction,$$\Delta H$$=150KJ and $$\Delta S$$= 100JK$$^{-1}$$ at 300K. $$\Delta $$G would be ________.
  • Zero
  • 300KJ
  • 330KJ
  • 120KJ

Correct relation among the following.
  • $$\Delta G_{system} = \Delta S_{total}$$
  • $$\Delta G_{system}=\Delta H_{system}-T\Delta S_{system}$$
  • $$\Delta $$G =$$\Delta $$ H + T $$\Delta $$S
  • $$\Delta S=\frac{\Delta G+\Delta H}{\Delta T}$$

Gibbs -Helmholtz equation is______
  • $$\Delta $$G=$$\Delta $$ H-T $$\Delta $$ S
  • $$\Delta $$G=$$\Delta $$H- $$\Delta $$S
  • $$\Delta $$G =T$$\Delta $$ H-T$$\Delta $$ S
  • $$\Delta $$G=T $$\Delta $$ H- $$\Delta $$ S
Which of the following statements is incorrect?
  • It is not possible to compress a gas at a temperature below $$T_c$$
  • At a temperature below $$T_c$$, the molecules are close enough for the attractive forces to act, and condensation occur
  • No condensation takes place above $$T_c$$
  • The kinetic energy of the gas molecules is higher above $$T_c$$, and the attraction between them decreases
Identify the correct statement for change of Gibbs energy for a system ($$\Delta$$G$$_{system}$$) at constant temperature and pressure:
  • If $$\Delta$$G$$_{system}$$ > 0, the process is spontaneous
  • If $$\Delta$$G$$_{system}$$ = 0, the system has attained equilibrium
  • If $$\Delta$$G$$_{system}$$ = 0, the system is still moving in a particular direction
  • If $$\Delta$$G$$_{system}$$ < 0, the process is not spontaneous
The equilibrium partial pressure of $$N_2, H_2$$ and $$NH_3$$ are $$4, 4$$ and $$8$$ atm respectively. The value of $$K_p$$ for the Haber's process in $$atm^{-1}$$ is:
  • $$1/4$$
  • $$1/2$$
  • $$4$$
  • $$2$$
Cell reaction is spontaneous when : 
  • G is negative
  • G is positive
  • E is positive
  • E is negative
The specific heat capacity of water is:
  • $$1\ cal\ g^{-1}$$
  • $$10\ cal\ g^{-1}$$
  • $$2\ cal\ g^{-1}$$
  • $$30\ cal\ g^{-1}$$
Which of the following parameters does not characterize the thermodynamic state of matter?
  • temperature
  • pressure
  • work
  • volume
Metabolism is the stepwise breakdown of the food we eat to provide energy for growth
and function. A general overall equation for this complex process represents the
degradation of glucose $$(C_{6}H_{12}O_{6})$$   to   $$CO_{2}$$    and   $$H_{2}O$$. This metabolic process involves many
steps and its enthalpy $$(\Delta H)$$ is called the enthalpy of combustion. This is because the same
quantity of heat is evolved whether we burn 1 mole of glucose in air or let the metabolic
process break it down. Which of the following equations can be used to calculate the
standard enthalpy of the metabolic process correctly?
  • $$H^{o} = [\Delta_{f}H^{o} (CO_{2})+ \Delta_{f}H^{o} (H_{2}O)] [\Delta_{f}H^{o} (C_{6}H_{12}O_{6}) + \Delta_{f}H^{o} (O_{2})]$$
  • $$H^{o} = [3\Delta_{f}H^{o} (CO_{2})+ 3\Delta_{f}H^{o} (H_{2}O)] [\Delta_{f}H^{o} (C_{6}H_{12}O_{6}) + 3\Delta_{f}H^{o} (O_{2})]$$
  • $$H^{o} = [3\Delta_{f}H^{o} (CO_{2})+ 6\Delta_{f}H^{o} (H_{2}O)] [\Delta_{f}H^{o} (C_{6}H_{12}O_{6}) + 3\Delta_{f}H^{o} (O_{2})]$$
  • $$H^{o} = [6\Delta_{f}H^{o} (CO_{2})+ 6\Delta_{f}H^{o} (H_{2}O)] [\Delta_{f}H^{o} (C_{6}H_{12}O_{6}) + 6\Delta_{f}H^{o} (O_{2})]$$
The total heat content of a system is
  • Entropy
  • Free energy
  • Enthalpy
  • Kinetic energy
$$n \ moles$$ of gas an ideal monatomic gas is confined in a cylinder A of volume $$V_{0}$$, pressure $$P_{0}$$ and temperature $$T_{0}$$, this cylinder is connected to another cylinder B with the help of tube of a negligible volume. The cylinder B is fitted with a movable piston which can be adjusted from outside. Initially, the piston is adjusted so that volume of B is 7$$V_{0}$$ and B is evacuated and then stopcork is opened so that gas expands and occupies the volume $$8V_{0}$$. [System is thermally isolated from the surroundings].

During this free expansion, the internal energy of the system

75675_6d51079b936b46eb9d945e396da88992.png
  • Increases
  • Decreases
  • Remains constant
  • Nothing can be said
A sample of oxygen gas expands its volume from $$3\ L\ to\ 5\ L$$ against a constant pressure of $$3\ atm$$. If work done during expansion is used to heat 10 mole of water initially present at $$290\ K$$, its final temperature will be (specific heat capacity of water = 4.18 J/kg):
  • $$292.0\ K$$
  • $$298.0\ K$$
  • $$290.8\ K$$
  • $$293.7\ K$$
Water of mass $$m_2$$ = 1 kg is contained in a copper calorimeter of mass $$m_1$$  = 1 kg. Their common temperature t = $$10^{0}C$$. Now a piece of ice of mass $$m_3$$  = 2 kg and temperature is $$-11^{0}C$$ dropped into the calorimeter. Neglecting any heat loss, the final temperature of system is. [specific heat of copper = 0.1 Kcal/ kg$$^{0}C$$, specific heat of water = 1 Kcal/kg$$^{0}C$$, specific heat of ice = 0.5 Kcal/kg$$^{0}C$$, latent heat of fusion of ice = 78.7 Kcal/kg]
  • $$0^{0}C$$
  • $$4^{0}C$$
  • $$- 4^{0}C$$
  • $$- 2^{0}C$$
Specific heat of a gas undergoing adiabatic change is
  • 1
  • 0
  • 4
  • 6
The energy stored in water formed from ice is:
  • latent heat of fusion of ice
  • $$80\ cal\ g^{-1}$$
  • latent heat of boiling
  • latent heat of fusion of water
Specific heat may be defined as:
  • heat capacity at constant volume
  • heat capacity at constant pressure
  • heat capacity mol$$^{-1}$$
  • heat capacity g$$^{-1}$$
The temperature at which the reaction $$AgO(s)  \rightarrow Ag(s) + \frac{1}{2} O_2(g)$$ is at equilibrium is?
Given  $$\Delta H = 30.5  KJ  mol^{-1}$$ and $$\Delta  S = 0.066 KJK^{-1}  mol^{-1}$$
  • 462.12 K
  • 362.12 k
  • 262.12 k
  • 562.12 k
Which of the following statement(s) is/are false?
  • $$\Delta_rS$$ for $$\frac {1}{2} Cl_2(g)\rightarrow Cl(g)$$ is positive.
  • $$\Delta E < 0$$ for combustion of $$CH_4(g)$$ in a sealed container with rigid adiabatic system.
  • $$\Delta G$$ is always zero for a reversible process in a closed system.
  • $$\Delta G^o$$ for an ideal gas reaction is a function of pressure.
Actual flame temperature is always lower than the adiabatic flame temperature, because there is ______________.
  • no possibility of obtaining complete combustion at high temperature.
  • always loss of heat from the flame.
  • both (a) and (b).
  • neither (a) nor (b).
The internal energy of a compressed real gas, as compared to that of the normal gas at the same temperature, is
  • less
  • more
  • sometimes less, sometimes more
  • none of these
Two bodies at different temperatures are mixed in a calorimeter. Which of the following quantities remains conserved?
  • sum of the temperatures of the two bodies
  • total heat of the two bodies
  • total internal energy of the two bodies
  • internal energy of each body
Hess's law is applicable for the determination of heat of:
  • reaction
  • transition
  • formation
  • all of the above
Which specific process has negative value of specific heat?
  • Saturated vapours
  • Ice
  • Water
  • Vapours
The heat required to raise the temperature of a body by 1 K is called :
  • specific heat
  • thermal capacity
  • water equivalent
  • none of these
A liquid boils at such a temperature at which the saturated vapour pressure, as compared to atmospheric pressure, is 
  • one-third
  • equal
  • half
  • double
The internal energy of a gram-molecule of an ideal gas depends on 
  • pressure alone
  • volume alone
  • temperature alone
  • both pressure as well as temperature
6.80 g of $$NH_3$$; is passed over heated CuO. The standard heat enthalpies of $$NH_{3}$$, $$CuO(s)$$ and $$H_2O(l)$$ are -46.0, -155.0 and $$-285 0 \: kJ \: mol^{-1}$$ respectively and the change is.
$$NH_3 +(3/2)CuO\longrightarrow \frac{1}{2}N_2(g)+ (3/2)H_2O(l) +(3/2)Cu(s)$$.
If the enthalpy change is 
  • -50
  • -59.6
  • 60
  • 30
The enthalpy change for the reaction is:
                   $$XeF_4\longrightarrow Xe^+ +  F^- + F_2 + F; \:  \ \ \ \ \Delta H=?$$

The average $$Xe-\! \! \! -F$$ bond energy is $$34 \:kcal \:mol^{-1}$$ . $${IE}_1$$ of Xe is $$279 \: kcal \: mol^{-1}$$ and electron affinity of F is $$85 \:kcal \:mol^{-1}$$ and $$e_{F-\! \! \! -F} = 38 \:kcal \: mol^{-1}$$.
  • $$345 \:kcal \: mol^{-1}$$
  • $$292 \:kcal \: mol^{-1}$$
  • $$174 \:kcal \: mol^{-1}$$
  • None of these
The internal energy of a piece of lead when beaten by a hammer will
  • increase
  • decrease
  • remain constant
  • sometimes increases and sometimes decreases
For a given reaction, $$ \Delta H=35.5\ kJ\ mol^{-1}$$ and $$ \Delta S=83.6\ J\ K^{-1}\ mol^{-1}. The reaction is spontaneous at:
(Assume that $$ \Delta H$$ and $$ \Delta S$$ so not vary with temperature)
  • $$T<425K$$
  • $$T>425K$$
  • all temperatures
  • $$T>298K$$
Hess's law is related to:
  • equilibrium constant
  • change in heat during a reaction
  • rates of reaction
  • influence of pressure on volume of a gas
The heat capacities of the following gases at room temperature are such that :
  • $$NH_3 > CO_2 = O_2 = N_2 > Ar$$
  • $$NH_3 = CO_2 > O_2 > N_2 > Ar$$
  • $$NH_3 > CO_2 > O_2 = N_2 > Ar$$
  • $$NH_3 > CO_2 > O_2 > N_2 > Ar$$
What is the free energy change $$(\Delta G)$$ when 1.0 mole of water at $$100^{\circ}\! C$$ and 1 atm pressure is converted into steam at $$100^{\circ}\! C$$ and 1 atm pressure?
  • 80 cal
  • 540 cal
  • 620 cal
  • zero
Chemical reaction is invariably associated with the transfer of energy either in the form of heat or light. In the laboratory, heat changes in physical and chemical processes are measured with an instrument called Calorimeter. Heat change in the process is calculated as :

$$q = ms\Delta T$$ ........ $$s= specific\quad heat$$
  $$= c\Delta T$$ ....... $$c= heat\quad capacity$$

Heat of reaction at constant volume is measured using bomb Calorimeter.
$$q_V = \Delta U = $$internal energy change

Heat of reaction at constant pressure is measured using bomb Calorimeter.
$$q_P = \Delta H$$
$$q_P = q_V + P\Delta V$$
$$\Delta H = \Delta U + \Delta nRT$$
The heat capacity of a bomb calorimeter is $$500  J  K^{ -1 }$$. When $$0.1  g$$ of Methane was burnt in this calorimeter, the temperature rose by $$2^{ \circ }C$$. The value of $$\Delta U$$ per mole will be :
  • $$-160 kJ$$
  • $$+260 kJ$$
  • $$-2 kJ$$
  • $$+2 kJ$$
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