CBSE Class 11 Chemistry Thermodynamics Worksheet Set C

Thermodynamics MCQ Questions with Answers Class 11 Chemistry 

Question- Identify the correct statement regarding a spontaneous process:

(a) Lowering of energy in the process is the only criterion for spontaneity.

(b) For a spontaneous process in an isolated system, the change in entropy is positive.

(c) Endothermic processes are never spontaneous.

(d) Exothermic processes are always spontaneous.

Answer-(b)

Question-The enthalpies of elements in their standard states are taken as zero. The enthalpy of formation of a compound

(a) is always negative

(b) is always positive

(c) may be positive or negative

(d) is never negative

Answer-(c)

Question- Pick out the wrong statement

(a) The standard free energy of formation of all elements is zero

(b) A process accompanied by decrease in entropy is spontaneous under certain conditions

(c) The entropy of a perfectly crystalline substance at absolute zero is zero

(d) A process that leads to increase in free energy will be spontaneous

Answer-(d)

Question- Bond dissociation enthalpy of H₂, Cl₂ and HCl are 434 , 242 and 431 kJ mol^–1 respectively. Enthalpy of formation of HCl is:

(a) 93 kJ mol^–1

(b) – 245 kJmol^–1

(c) – 93 kJmol^–1

(d) 245 kJmol^–1

Answer-(c)

Question-The enthalpy change on breaking one mole of bonds completely to obtain atoms in the gas phase is known as

(a) enthalpy of atomization.

(b) enthalpy of formation

(c) enthalpy of sublimation

(d) enthalpy of vaporization

Answer-(a)

Question-The enthalpy change for a reaction does not depend upon

(a) use of different reactants for the same product

(b) the nature of intermediate reaction steps

(c) the differences in initial or final temperatures of involved substances

(d) the physical states of reactants and products

Answer-(b)

Question-The heat of combustion of a substance is :

(a) Always positive

(b) Always negative

(c) Numerically equal to the heat of formation

(d) Unpredictable

Answer-(b)

Question-Given that heat of neutralisation of strong acid and strong base is – 57.1 kJ. The heat produced when 0.25 mole of HCl is neutralised with 0.25 mole of NaOH in aqueous solution is :

(a) 14.275 kJ

(b) 57.1 kJ

(c) 22.5 kJ

(d) 28.6 kJ

Answer-(a)

Question-Hess’s law is used to calculate :

(a) enthalpy of reaction.

(b) entropy of reaction

(c) work done in reaction

(d) All of the above

Answer-(a)

Question-For most of the ionic compounds, sol ΔH is …………and the dissociation process is…………….

(a) positive ,exothermic

(b) negative, exothermic

(c) positive, endothermic

(d) negative,endothermic

Answer-(c)

Question-A chemical reaction will be spontaneous if it is accompanied by a decrease of

(a) entropy of the system.

(b) enthalpy of the system.

(c) internal energy of the system.

(d) free energy of the system.

Answer-(d)

More Question

Instructions:

1. All questions are compulsory.

2. Please give the explanation for the answer where applicable.

Q1 -Explain the term system, surrounding and universe with example. 

Q2 - Express the change in internal energy of a system when

(i) No heat is absorbed by the system from the surroundings, but work (w) is done on the system. What type of wall does the system have?

(ii) No work is done on the system, but q amount of heat is taken out from the system and given to the surroundings. What type of wall does the system have?

(iii) w amount of work is done by the system and q amount of heat is supplied to the system. What type of system would it be? 

Q3 -Two moles of an ideal gas initially at 270C and one atmospheric pressure are compressed isothermally and reversibly till the final pressure of the gas is 10 atm. Calculate q, w and U for the process. 

Q4 - Define Exothermic and Endothermic reactions. 

Q5 - Define the Enthalpy of neutralization of a reaction. 

Q6 - Define the term Enthalpy of ionization. 

Q7 - Give the first law of thermodynamics. 

Q8 -Give the first law of thermodynamics. Derive a mathematical expression for the first law of thermodynamics.

Q9 - Give the Hess’s Law of constant heat? 

Please refer to the link below for CBSE Class 11 Chemistry Thermodynamics Worksheet Set C