# NCERT solutions for Chemistry Part 1 and 2 Class 11 chapter 6 - Thermodynamics [Latest edition]

## Chapter 6: Thermodynamics

EXERCISES
EXERCISES [Pages 189 - 191]

### NCERT solutions for Chemistry Part 1 and 2 Class 11 Chapter 6 ThermodynamicsEXERCISES [Pages 189 - 191]

EXERCISES | Q 6.1 | Page 189

A thermodynamic state function is a quantity ______.

• used to determine heat changes

• whose value is independent of path

• used to determine pressure-volume work

• whose value depends on temperature only.

EXERCISES | Q 6.2 | Page 189

For the process to occur under adiabatic conditions, the correct condition is ______.

• ΔT = 0

• Δp = 0

• q = 0

• w = 0

EXERCISES | Q 6.3 | Page 189

The enthalpies of all elements in their standard states are ______.

• unity

• zero

• < 0

• different for each element

EXERCISES | Q 6.4 | Page 189

ΔUof combustion of methane is – X kJ mol–1. The value of ΔH is ______.

• = ΔU

• > ΔU

• < ΔU

• = 0

EXERCISES | Q 6.5 | Page 189

The enthalpy of combustion of methane, graphite and dihydrogen at 298 K are, - 890.3 kJ mol-1 -393.5 kJ mol-1, and - 285.8 kJ mol-1 respectively. Enthalpy of formation of CH4(g) will be ______.

• - 74.8 kJ mol-1

• - 52.27 kJ mol-1

• + 74.8 kJ mol–1

• + 52.26 kJ mol-1

EXERCISES | Q 6.6 | Page 189

A reaction, A + B → C + D + q is found to have a positive entropy change. The reaction will be ______.

• possible at high temperature

• possible only at low temperature

• not possible at any temperature

• possible at any temperature

EXERCISES | Q 6.7 | Page 189

In a process, 701 J of heat is absorbed by a system and 394 J of work is done by the system. What is the change in internal energy for the process?

EXERCISES | Q 6.8 | Page 189

The reaction of cyanamide, NH2CN(s), with dioxygen was carried out in a bomb calorimeter, and ΔUwas found to be - 742.7 kJ mol-1at 298 K. Calculate enthalpy change for the reaction at 298 K.

$\ce{NH_2 CN(g) + 3/2 O_2(g) -> N_2(g) + CO_2(g) + H_2O(l)}$

EXERCISES | Q 6.9 | Page 189

Calculate the number of kJ of heat necessary to raise the temperature of 60.0 g of aluminium from 35°C to 55°C. Molar heat capacity of Al is 24 J mol-1 K-1.

EXERCISES | Q 6.10 | Page 190

Calculate the enthalpy change on freezing of 1.0 mol of water at 10.0°C to ice at - 10.0°C. ΔfusH = 6.03 kJ mol-1 at 0°C.

Cp[H2O(l)] = 75.3 J mol-1 K-1

Cp[H2O(s)] = 36.8 J mol-1 K-1

EXERCISES | Q 6.11 | Page 190

Enthalpy of combustion of carbon to CO2 is –393.5 kJ mol–1. Calculate the heat released upon formation of 35.2 g of CO2 from carbon and dioxygen gas.

EXERCISES | Q 6.12 | Page 190

Enthalpies of formation of CO(g), CO2(g), N2O(gand N2O4(gare -110 kJ mol-1, - 393 kJ mol-1, 81 kJ mol-1 and 9.7 kJ mol-1 respectively. Find the value of ΔrH for the reaction:

$\ce{N2O_{4(g)} + 3CO_{(g)} → N2O_{(g)} + 3CO_{2(g)}}$

EXERCISES | Q 6.13 | Page 190

Given

$\ce{N_{2(g)} + 3H_{2(g)} -> 2NH_{3(g)}}$; ΔrHθ = –92.4 kJ mol–1

What is the standard enthalpy of formation of NH3 gas?

EXERCISES | Q 6.14 | Page 190

Calculate the standard enthalpy of formation of CH3OH(l) from the following data:

$\ce{CH3OH_{(l)} + 3/2 O2_{(g)} →CO_{2(g)} + 2H2O_{(l)}}$ ; ΔrHθ = –726 kJ mol–1

$\ce{C_{(g)} + O_{2(g)} →CO_{2(g)}}$ ; ΔcHθ = –393 kJ mol–1

$\ce{H_{2(g)} +1/2 O_{2(g)} → H2O_{(l)}}$ ; ΔfHθ = –286 kJ mol–1.

EXERCISES | Q 6.15 | Page 190

Calculate the enthalpy change for the process

$\ce{CCl_4 (g) → C(g) + 4Cl(g)}$

and calculate bond enthalpy of C–Cl in CCl4(g).

ΔvapHθ (CCl4) = 30.5 kJ mol–1.

ΔfHθ (CCl4) = –135.5 kJ mol–1.

ΔaHθ (C) = 715.0 kJ mol–1, where ΔaHθ is enthalpy of atomisation

ΔaHθ (Cl2) = 242 kJ mol–1

EXERCISES | Q 6.16 | Page 190

For an isolated system, ΔU = 0, what will be ΔS?

EXERCISES | Q 6.17 | Page 190

For the reaction at 298 K,

$\ce{2A + B → C}$

ΔH = 400 kJ mol-1 and ΔS = 0.2 kJ K-1 mol-1

At what temperature will the reaction become spontaneous considering ΔH and ΔS to be constant over the temperature range?

EXERCISES | Q 6.18 | Page 190

For the reaction, $\ce{2Cl_{(g)} → Cl_{2(g)}}$, what are the signs of ΔH and ΔS?

EXERCISES | Q 6.19 | Page 190

For the reaction

$\ce{2A_{(g)} + B_{(g)} → 2D_{(g)}}$

ΔUθ = –10.5 kJ and ΔSθ= –44.1 JK–1.

Calculate ΔGθ for the reaction, and predict whether the reaction may occur spontaneously.

EXERCISES | Q 6.20 | Page 191

The equilibrium constant for a reaction is 10. What will be the value of ΔG? R = 8.314 JK–1 mol–1,T = 300 K.

EXERCISES | Q 6.21 | Page 191

Comment on the thermodynamic stability of NO(g), given

$\ce{1/2 N_2 (g) + 1/2 O2(g) → NO(g)}$; ΔrHθ = 90 kJ mol–1

$\ce{NO(g) +1/2 O2(g) → NO2(g)}$ : ΔrHθ= –74 kJ mol–1

EXERCISES | Q 6.22 | Page 191

Calculate the entropy change in surroundings when 1.00 mol of H2O(l) is formed under standard conditions. ΔfHθ = –286 kJ mol–1.

EXERCISES

## NCERT solutions for Chemistry Part 1 and 2 Class 11 chapter 6 - Thermodynamics

NCERT solutions for Chemistry Part 1 and 2 Class 11 chapter 6 (Thermodynamics) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CBSE Chemistry Part 1 and 2 Class 11 solutions in a manner that help students grasp basic concepts better and faster.

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Concepts covered in Chemistry Part 1 and 2 Class 11 chapter 6 Thermodynamics are Thermodynamic Terms, The State of the System, The Internal Energy as a State Function - Work, The Internal Energy as a State Function - Heat, The Internal Energy as a State Function - The General Case, Work, Enthalpy, H - A Useful New State Function, Enthalpy, H - Extensive and Intensive Properties, Enthalpy, H - Heat Capacity, Enthalpy, H - The Relationship Between Cp and Cv for an Ideal Gas, Measurement of ∆U and ∆H Calorimetry - ∆U Measurements, Measurement of ∆U and ∆H Calorimetry - ∆H Measurements, Standard Enthalpy of Reactions, Enthalpy Changes During Phase Transformations, Standard Enthalpy of Formation, Thermochemical Equations, Hess’ Law of Constant Heat Summation, Standard Enthalpy of Combustion, Enthalpy of Atomization, Bond Enthalpy, Enthalpy of Solution, Lattice Enthalpy, Is Decrease in Enthalpy a Criterion for Spontaneity, Entropy and Spontaneity, Gibbs Energy and Spontaneity, Gibbs Energy Change and Equilibrium.

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