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The internal energy change (in J ) when 90   g of water undergoes complete evaporation at 100 ° C is .............. (Given : ΔH vap for water at 373   K = 41   kJ / mol , R = 8 . 314   JK - 1   mol - 1 )

Correct answer

189494

Step-by-step solution

Number of moles of water = 90 18 = 5   moles Δ H = Δ U + Δ n g RT 41000 X 5 = Δ U + 5 × 8 . 314 × 373 205000 = Δ U + 15505 . 61 Δ U = 189494 . 39   J = 189494   J

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