JEE Main 2020 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 2 September 2020, Shift 1, Chemistry Q46

Question 46 of 75 in this shift, Chemistry question 21 of 25.

The internal energy change (in J) when 90 g of water undergoes complete evaporation at

100^\circ

C is ______. (Given :

\Delta H_{vap}

for water at 373 K = 41 kJ/mol,

R=8.314\ \mathrm{JK^{-1}\ mol^{-1}}

)

Official answer

189000.00 to 190000.00

NTA final key (Sep 2020). Any value in the range scored.

Chapter: Thermodynamics (Chemistry)
Topic: Enthalpy and Hess's Law
Idea tested: Relation Between ΔH and ΔU

Same idea in other shifts

Asked 10× in all

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26 Aug 2021, Shift 2 · Q53For water $\Delta_{\mathrm{vap}}H$ = 41 kJ $\mathrm{mol^{-1}}$ at 373 K and 1 bar pressure. Assuming that water vapour is an ideal gas…MediumNumerical value

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.