<\/span><\/h2>\nThe sixth chapter in the NCERT class 11 textbook is \u201cThermodynamics\u201d. Thermodynamics is a branch of science that deals with the relationship between heat and other forms of energy. A part of the universe where observations are made is called a system. The surrounding of a system is the part of the universe that does not contain the system.<\/p>\n
Based on the exchange of energy and matter, thermodynamic systems can be classified into 3 types: a closed system, an open system, and an isolated system. In a closed system, only energy can be exchanged with the surroundings. In an open system energy as well as matter can be exchanged with the surroundings. In an isolated system, both energy and matter cannot be exchanged with the surroundings.<\/p>\n
NCERT Class 11 Chemistry Chapter 6, Thermodynamics is from chemistry Part 1 and belongs to Unit 6. Unit 6 along with Unit 4, Unit 5 and Unit 6 and Unit 7 holds a weightage of 21 marks. In this chapter, the students will be introduced to Thermodynamics, Its meaning, application, and uses. This chapter will help students build a foundation for Grade 12 and further competitive exams.<\/p>\n
Subtopics included in Class 11 Chemistry Chapter 6 Chemical Thermodynamics<\/p>\n
\n- Thermodynamic Terms\n
\n- The System and the Surroundings<\/li>\n
- Types of Thermodynamic Systems<\/li>\n
- State of the System<\/li>\n
- Internal Energy as a State Function<\/li>\n<\/ul>\n<\/li>\n
- Applications\n
\n- Work<\/li>\n
- Enthalpy, H<\/li>\n<\/ul>\n<\/li>\n
- Measurement Of \u0394U And \u0394H: Calorimetry<\/li>\n
- Enthalpy Change and Reaction Enthalpy<\/li>\n
- Enthalpies For Different Types Of Reactions<\/li>\n
- Spontaneity<\/li>\n
- Gibbs Energy Change And Equilibrium<\/li>\n<\/ul>\n
We cover all exercises in Chapter 6 \u2013 all 22 questions with solutions.<\/p>\n
Other than given exercises students are encouraged to practice all the solved examples given in the book to clear their concepts on Thermodynamics.<\/p>\n
<\/span>Access NCERT Solutions for Class 11 Chemistry Chapter 6<\/span><\/h2>\n<\/span>Question 1. Choose the correct answer:<\/strong>
A thermodynamic state junction is a quantity<\/strong>
(i) used to determine heat changes<\/strong>
(ii) whose value is independent of the path<\/strong>
(iii) used to determine pressure-volume work<\/strong>
(iv) whose value depends on temperature only.<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>(ii) whose value is independent of the path<\/p>\n<\/span>Question 2. For the process to occur under adiabatic conditions, the correct condition is:<\/strong>
(i) \u2206T= 0 (ii) \u2206p = 0<\/strong>
(iii) q = 0 (iv) w = 0<\/strong><\/span><\/h3>\nAns.<\/strong>\u00a0(iii) q = 0<\/p>\n<\/span>Question 3. The enthalpies of all elements in their standard states are: \u2018<\/strong>
(i) unity (ii) zero<\/strong>
(iii) < 0 (iv) different for each element<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>\u00a0(ii) zero<\/p>\nQuestion 4.<\/strong>
![\"1\"](\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/07\/1-3.png\")
Answer:<\/strong>
![\"2\"](\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/07\/2-2.png\")
<\/p>\n<\/span>Question 5. The enthalpy of combustion of methane, graphite, and dihydrogen at 298 K are -890.3 KJ mol-1<\/sup>, \u2013 393.5\u00a0KJ mol-1,<\/sup>\u00a0and \u2013 285.8 KJ mol-1<\/sup>\u00a0respectively. Enthalpy of formation of CHJg) will be<\/strong>
(i) \u2013 74.8\u00a0KJ mol-1\u00a0<\/sup>\u00a0(ii) \u2013 52.27 KJ mol-1<\/sup><\/strong>
(iii) + 74.8 KJ mol-1<\/sup>\u00a0(iv) + 52.26 KJ mol-1<\/sup><\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>\u00a0As per the available data :
![\"3\"](\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/07\/3-2.png\")
<\/p>\n<\/span>Question 6. A reaction, A + B\u2014>C + D + q is found to have a positive entropy change. The reaction will be<\/strong>
(i) possible at high temperature (ii) possible only at low temperature<\/strong>
(iii) not possible at any temperature (iv) possible at any temperature<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>\u00a0(iv) possible at any temperature<\/p>\n<\/span>Question 7. In a process, 701 ] 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?<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>\u00a0Heat absorbed by the system, q = 701 J Work done by the system = \u2013 394 J Change in internal energy (\u2206U) = q + w = 701 \u2013 394 = 307 J.<\/p>\n<\/span>Question 8. The reaction of cyanamide, NH2<\/sub>CN(s) with dioxygen was carried out in a bomb calorimeter and \u2206U was found to be -742,7\u00a0KJ-1 <\/sup>mol-1\u00a0<\/sup>at 298 K. Calculate the enthalpy change for the reaction at 298 K.<\/strong>NH2<\/sub>CN\u00a0(S) + 3\/202(g) \u2014\u2013>N2<\/sub>(g) + CO2<\/sub>(g) + H2<\/sub>0(Z)<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>\u00a0\u2206U = \u2013 742.7\u00a0KJ-1 <\/sup>mol-1\u00a0<\/sup>; \u2206ng<\/sup>\u00a0= 2 \u2013 3\/2 = + 1\/2 mol.
R = 8.314 x 10-3KJ-1 <\/sup>mol-1\u00a0<\/sup>; T = 298 K
According to the relation,\u2206H = \u2206U+\u2206ng <\/sup>RT
\u2206H = (- 742.7 kj) + (1\/2 mol) x (8.314 x10-3\u00a0<\/sup>KJ-1 <\/sup>mol-1\u00a0<\/sup>) x (298 K)
= \u2013 742.7 kj + 1.239 kj = \u2013 741.5 kj.<\/p>\n<\/span>Question 9. Calculate the number of kj of heat necessary to raise the temperature of 60 g of aluminum from 35\u00b0C to 55\u00b0C. The molar heat capacity of Al is 24 J mol-1<\/sup>\u00a0K-1<\/sup>.<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>No. of moles of Al (m) = (60g)\/(27 g mol-1)<\/sup>\u00a0= 2.22 mol
Molar heat capacity (C) = 24 J mol-1<\/sup>\u00a0K-1<\/sup>.
Rise in temperature (\u2206T) = 55 \u2013 35 = 20\u00b0C = 20 K
Heat evolved (q) = C x m x T = (24\u00a0J mol-1<\/sup>\u00a0K-1<\/sup>) x (2.22 mol) x (20 K)
= 1065.6 J = 1.067 kj<\/p>\n<\/span>Question 10. Calculate the enthalpy change on freezing of 1.0 mol of water at 10.0\u00b0C to ice at \u2013 10.0\u00b0C. A, H = 6.03 KJ mot1 at 0\u00b0C. Cp [H20(l)J = 75.3\u00a0J mol-1<\/sup>\u00a0K-1<\/sup>; Cp [H20(s)J = 36.8\u00a0J mol-1<\/sup>\u00a0K-1<\/sup>.<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>The change may be represented as:
![\"4\"](\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2021\/07\/4-1.png\")
<\/p>\n<\/span>Question 11. The enthalpy of combustion of carbon to carbon dioxide is \u2013 393.5 J mol-1. <\/sup>Calculate the heat released upon formation of 35.2 g of\u00a0C02\u00a0<\/sub>from carbon and oxygen gas.<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>The combustion equation is:
C(s) + 02\u00a0<\/sub>(g) \u2014\u2013> C02<\/sub>(g); AcH = \u2013 393.5\u00a0KJ mol-1<\/sup>
The heat released in the formation of 44g of C02<\/sub>\u00a0= 393.5 kj
Heat released in the formation of 35.2 g of C02<\/sub>=(393.5 KJ) x (35.2g)\/(44g) = 314.8 kj<\/p>\n<\/span>Question 12. Calculate the enthalpy of the reaction:<\/strong>
N2<\/sub>04<\/sub>(g) + 3CO(g) \u2014\u2014\u2014->N2<\/sub>0(g) + 3CO2<\/sub>(g)<\/strong>
Given that;\u2206f <\/sub>H\u2013<\/sup>CO(g) = \u2013 110 kj mot-1<\/sup>; \u2206f<\/sub>HC02<\/sub>(g) = \u2013 393 kj mol-1<\/sup><\/strong>
\u2206f<\/sub>HN2<\/sub>0(g) = 81 kj mot-1<\/sup>; \u2206f<\/sub>N2<\/sub>O4<\/sub>(g) = 9.7 kj mol-1<\/sup><\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>\u00a0Enthalpy of reaction (\u2206r<\/sub>,H) = [81 + 3 (- 393)] \u2013 [9.7 + 3 (- 110)]
= [81 \u2013 1179] \u2013 [9.7 \u2013 330] = \u2013 778 kj mol-1<\/sup><\/p>\n<\/span>Question 13. Given : N2<\/sub>(g) + 3H2<\/sub>(g) \u2014\u2014\u2014\u2014> 2NH3<\/sub>(g); \u2206r H\u2013<\/sup><\/sub>\u00a0= -92.4 kj mot-1\u00a0<\/sup>What is the standard\u00a0<\/strong>enthalpy of formation of NH3<\/sub>\u00a0gas?<\/strong><\/span><\/h3>\nAnswer:\u00a0<\/strong>\u00a0\u2206H\u2013<\/sup>\u00a0NH3<\/sub>\u00a0(g) = \u2013 (92.4)\/2 = \u2013 46.2 kj mol-1<\/sup><\/p>\n<\/span>Question 14. Calculate the standard enthalpy of the formation of CH3<\/sub>OH. from the following data:<\/strong>
(i) CH3<\/sub>OH(l) + 3\/2 02<\/sub>\u00a0(g) \u2014\u2014\u2014-> CO
![\"NCERT](\"https:\/\/www.kopykitab.com\/blog\/wp-content\/uploads\/2020\/09\/NCERT-Solutions-For-Class-11-Chemistry-Chapter-6-Thermodynamics-1.jpg\")
<\/p>\n