An alloy of mass 0.2 kg (30\% copper, 70\% nickel by mass) is dropped into a container of water equivalent 20 g holding 180 g of water at 15°C. Equilibrium is reached at 25°C. c w = 4200 , c C u =

Question

An alloy of mass 0.2 kg (30\% copper, 70\% nickel by mass) is dropped into a container of water equivalent 20 g holding 180 g of water at 15°C. Equilibrium is reached at 25°C. c w ​ = 4200 , c C u ​ = 420 , c N i ​ = 460 J / ( kg ∘ C ) . Find the initial temperature of the alloy in °C.

TestHub · Accepted Answer

Alloy: c = 0.3 ( 420 ) + 0.7 ( 460 ) = 448 J / ( kg ∘ C ) , capacity 89.6 J / ∘ C . Water plus container: 0.2 kg of water, 840 J/°C, gains 8400 J. 89.6 ( T − 25 ) = 8400 , so T = 118.7 5 ∘ C .

Physics - Heat & Thermo Question with Solution | TestHub

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