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Friday, 9 October

JEE Main Chemistry · Thermodynamics (Chemistry)

Hess's Law

Hess's Law (Thermodynamics (Chemistry)) was asked 4 times in 4 JEE Main shifts, 2017–2026, out of the 42 shifts Lumi analysed. 2 of the 4 had a numerical answer.

Times asked
4
in 4 shifts
Years
2017–2026
Usual format
Numerical value
Calculation
Pattern
Frequent
repeats across shifts

How it is asked

  • Enthalpy of formation via hess cycle
  • Enthalpy change via hess's law

Difficulty

Easy 3Medium 0Hard 1

Where it sits

Chapter: Thermodynamics (Chemistry). Topic: Enthalpy and Hess's Law, 24 questions over 14 ideas.

Other repeat ideas in this topic

Every time it came

All 4 questions

Newest first, each with its options and official answer.

  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. 25 Jul 2022, Shift 1 · Q82The enthalpy of combustion of propane, graphite and dihydrogen at 298 K are −2220.0 kJ mol−1-2220.0\ \mathrm{kJ\,mol^{-1}},…EasyNumerical value
  4. 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