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Saturday, 31 October

JEE Main · Chemistry · Thermodynamics (Chemistry)

Relation Between ΔH and ΔU

JEE Main asked Relation Between ΔH and ΔU 10 times in 10 of the 108 shifts Lumi analysed, in 2020, 2021, 2022 and 2024. It belongs to Enthalpy and Hess's Law, in Thermodynamics (Chemistry) (Chemistry). The longest wait between two years asking it was 2 years. In 2020 and 2022 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
10
in 10 shifts
Years
4 of 8
First asked
2020
last in 2024
Pattern
Comes in cycles
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2020, 2021, 2022 and 2024. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.150.30’170.17’200.03’210.21’220’230.05’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 2 in 12 shifts · 2021: 1 in 24 shifts · 2022: 6 in 24 shifts · 2023: 0 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20250 of 8
  • 20241 of 18
  • 20230 of 12
  • 20226 of 24
  • 20211 of 24
  • 20202 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Numerical value is the usual form. Skill tested: calculation.

  • Identify incorrect thermodynamic relation
  • Internal energy change on vaporisation

Difficulty

Easy 4Medium 6Hard 0

9 of the 10 questions had a numerical answer.

Every question

All 10 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 8 Apr 2024, Shift 2 · Q84ΔvapH⊖\Delta_{vap}H^{\ominus} for water is +40.79 kJ mol−1+40.79\ \mathrm{kJ\,mol^{-1}} at 1 bar and 100 °C. Change in internal energy for this…EasyNumerical value
  2. 29 Jun 2022, Shift 2 · Q822.2 g of nitrous oxide (N2O\mathrm{N_2O}) gas is cooled at a constant pressure of 1 atm from 310 K to 270 K causing the compression of the…MediumNumerical value
  3. 28 Jun 2022, Shift 2 · Q82For combustion of one mole of magnesium in an open container at 300 K and 1 bar pressure, ΔCH⊖=−601.70\Delta_C H^{\ominus} = -601.70 kJ mol−1^{-1},…MediumNumerical value
  4. 26 Jun 2022, Shift 2 · Q84A fish swimming in water body when taken out from the water body is covered with a film of water of weight 36 g. When it is subjected to…MediumNumerical value
  5. 26 Jun 2022, Shift 1 · Q81For complete combustion of methanol CH3OH(l)+32O2(g)→CO2(g)+2H2O(l)\mathrm{CH_3OH(l)}+\frac{3}{2}\mathrm{O_2(g)}\rightarrow\mathrm{CO_2(g)}+2\mathrm{H_2O(l)} the…MediumNumerical value
  6. 28 Jul 2022, Shift 1 · Q62Which of the following relation is not correct ?EasySingle correct
  7. 26 Jul 2022, Shift 2 · Q83For the reaction H2F2(g)→H2(g)+F2(g)\mathrm{H_2F_2(g) \rightarrow H_2(g) + F_2(g)} ΔU\Delta U = −59.6 kJ mol−1\mathrm{mol^{-1}} at 27°C. The enthalpy change…EasyNumerical value
  8. 26 Aug 2021, Shift 2 · Q53For water ΔvapH\Delta_{\mathrm{vap}}H = 41 kJ mol−1\mathrm{mol^{-1}} at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas…MediumNumerical value
  9. 2 Sep 2020, Shift 2 · Q47The heat of combustion of ethanol into carbon dioxids and water is −327-327 kcal at constant pressure. The heat evolved (in cal) at constant…MediumNumerical value
  10. 2 Sep 2020, Shift 1 · Q46The internal energy change (in J) when 90 g of water undergoes complete evaporation at 100∘100^\circC is ______. (Given : ΔHvap\Delta H_{vap}…EasyNumerical value

Shifts: 2 Sep 2020, Shift 2, 2 Sep 2020, Shift 1, 26 Aug 2021, Shift 2, 26 Jun 2022, Shift 2, 26 Jun 2022, Shift 1, 28 Jun 2022, Shift 2, 29 Jun 2022, Shift 2, 26 Jul 2022, Shift 2, 28 Jul 2022, Shift 1, 8 Apr 2024, Shift 2.

Same topic

Other ideas in Enthalpy and Hess's Law

Enthalpy and Hess's Law has 23 ideas JEE Main has asked; 12 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas