Learn

Friday, 9 October

JEE Main 2023 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 11 April 2023, Shift 1, Chemistry Q83

Question 83 of 90 in this shift, Chemistry question 23 of 30, Section B.

Solid fuel used in rocket is a mixture of Fe2O3\mathrm{Fe_2O_3} and Al (in ratio 1:2). The heat evolved (kJ) per gram of the mixture is __________ (Nearest integer) Given: ΔHfθ(Al2O3)=−1700 kJ mol−1\Delta \mathrm{H_f^{\theta}(Al_2O_3)} = -1700\ \mathrm{kJ\ mol^{-1}} ΔHfθ(Fe2O3)=−840 kJ mol−1\Delta \mathrm{H_f^{\theta}(Fe_2O_3)} = -840\ \mathrm{kJ\ mol^{-1}} Molar mass of Fe, Al and O are 56, 27 and 16 g mol−1\mathrm{g\ mol^{-1}} respectively

Official answer

4

NTA final key.

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

Same topic in other shifts

All Enthalpy and Hess's Law questions
  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. 4 Apr 2026, Shift 1 · Q54Given below are two statements: Statement I: For an ideal gas, heat capacity at constant volume is always greater than the heat capacity…EasyTwo statements
  3. 4 Apr 2026, Shift 2 · Q71If 3.365 g of ethanol (ll) is burnt completely in a bomb calorimeter at 298.15 K, the heat produced is 99.472 kJ. The…HardNumerical value
  4. 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
  5. 3 Apr 2025, Shift 1 · Q71Given : ΔHsub⊖\Delta H^{\ominus}_{sub} [C (graphite)] = 710 kJ mol−1^{-1} ΔC−HH⊖\Delta_{C-H}H^{\ominus} = 414 kJ mol−1^{-1}…MediumNumerical value
  6. 3 Apr 2025, Shift 2 · Q53Given below are two statements: Statement I : When a system containing ice in equilibrium with water (liquid) is heated, heat is absorbed…EasyTwo statements

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.