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Friday, 16 October

JEE Main 2022 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 25 July 2022, Shift 1, Chemistry Q82

Question 82 of 90 in this shift, Chemistry question 22 of 30, Section B.

The enthalpy of combustion of propane, graphite and dihydrogen at 298 K are −2220.0 kJ mol−1-2220.0\ \mathrm{kJ\,mol^{-1}}, −393.5 kJ mol−1-393.5\ \mathrm{kJ\,mol^{-1}} and −285.8 kJ mol−1-285.8\ \mathrm{kJ\,mol^{-1}} respectively. The magnitude of enthalpy of formation of propane (C3H8\mathrm{C_3H_8}) is ______ kJ mol−1\mathrm{kJ\,mol^{-1}}. (Nearest integer)

Official answer

104

NTA final key (2022 Session 2).

Chapter
Thermodynamics (Chemistry)
Topic
Enthalpy and Hess's Law
Idea tested
Hess's Law

Same idea in other shifts

Asked 4× in all
  1. 2 Apr 2026, Shift 1 · Q54Consider the following data. (i) 2Al(s)+6HCl(aq)→Al2Cl6(aq)+3H2(g)+1200\mathrm{2Al(s)+6HCl(aq)\rightarrow Al_2Cl_6(aq)+3H_2(g)}+1200 kJ/mol (ii)…HardSingle correct
  2. 30 Jan 2024, Shift 2 · Q82Two reactions are given below:…EasyNumerical value
  3. 2 Apr 2017 (offline) · Q31Given C(graphite)+O2(g)→CO2(g)\mathrm{C_{(graphite)}+O_2(g)\rightarrow CO_2(g)} ; ΔrH∘=−393.5 kJ mol−1\Delta_rH^\circ=-393.5\ \mathrm{kJ\,mol^{-1}}…EasySingle correct

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.