Verified Solution • 2025–26 Session moderate

QJEEM22Ch378c: JEE Main 2022 Chemistry - Class 11 JEEM22Ch378c Solution: For combustion of one mole of magnesium in an open container at …

For combustion of one mole of magnesium in an open container at 300 K and 1 bar pressure, ΔCHΘ = −601.70 kJ mol−1, the magnitude of change in internal energy for the reaction is __________ kJ. (Nearest integer)

(Given : R = 8.3 J K−1 mol−1)

Step-by-Step Verified Solution

Mg(s)+12O2( g)⟶MgO(s)\mathrm{Mg}(\mathrm{s})+\frac{1}{2} \mathrm{O}_{2}(\mathrm{~g}) \longrightarrow \mathrm{MgO}(\mathrm{s})

ΔH=ΔU+ΔngRTΔng=−12−601.70=ΔU−12(8.3)(300)×10−3ΔU=−601.70+1.245ΔU≃−600 kJ

The magnitude of change in internal energy is 600 kJ600 \mathrm{~kJ} .

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