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Saturday, 31 October

JEE Main 2021 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 22 July 2021, Shift 2, Chemistry Q54

Question 54 of 90 in this shift, Chemistry question 24 of 30, Section B.

If the standard molar enthalpy change for combustion of graphite powder is −2.48×102-2.48 \times 10^2 kJ mol−1^{-1}, the amount of heat generated on combustion of 1 g of graphite powder is ________ kJ. (Nearest integer)

Official answer

21

NTA final key.

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

Same idea in other shifts

Asked 7× in all
  1. 8 Apr 2026, Shift 2 · Q74Consider the reaction 2H2S(g)+3O2(g)→2H2O(l)+2SO2(g)2\mathrm{H_2S(g)} + 3\mathrm{O_2(g)} \rightarrow 2\mathrm{H_2O(l)} + 2\mathrm{SO_2(g)} The magnitude of enthalpy…EasyNumerical value
  2. 5 Apr 2024, Shift 2 · Q83Combustion of 1 mole of benzene is expressed at C6H6(l)+152 O2(g)→6 CO2(g)+3 H2O(l)\mathrm{C_6H_6(l) + \frac{15}{2}\,O_2(g) \rightarrow 6\,CO_2(g) + 3\,H_2O(l)}. The…MediumNumerical value
  3. 6 Apr 2023, Shift 2 · Q83Consider the following data Heat of combustion of H2(g)\mathrm{H_2(g)} = −241.8-241.8 kJ mol−1^{-1} Heat of combustion of C(s)\mathrm{C(s)} =…MediumNumerical value
  4. 29 Jul 2022, Shift 2 · Q63C(s)+O2(g)→CO2(g)+400 kJ\mathrm{C(s)} + \mathrm{O_2(g)} \rightarrow \mathrm{CO_2(g)} + 400\ \mathrm{kJ}…MediumSingle correct
  5. 24 Jun 2022, Shift 2 · Q64At 25°C and 1 atm pressure, the enthalpies of combustion are given below: Substance | H2_2 | C (graphite) | C2_2H6_6(g)…MediumSingle correct
  6. 25 Jun 2022, Shift 2 · Q62At 25°C and 1 atm pressure, the enthalpy of combustion of benzene (l) and acetylene (g) are -3268 kJ mol−1\mathrm{kJ\ mol^{-1}} and -1300…MediumSingle 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 108 of the 174 JEE Main shifts held from 2017 to 2026.