Question

An aluminium block is heated to 100 °C and then placed immediately in 100 g of water which is initially at a temperature of 25.0 °C in a coffee cup calorimeter. Once the system reaches thermal equilibrium, the temperature of the water that surrounds the block is 28.0 °C. Calculate the mass of the aluminium block.

The specific heat capacity of Al is 0.900 J g^–1 K^–1 and for H2O is 4.184 J g^–1 K^–1

Answer 1

The final temperature at equilibrium is same for both .

Ans Given man o water = loog initial temperature g water (Tw.) =25€ = 298k " " "metal = 100c = 373K final temperature at equilibrium - 280 = 301k and Heat capacity of water - 41194 J/g-k Heat capacity of Al (metal) =0.900 J/g-k Now when a hot metal piece is put in water et releases heat as from (high temperature to low temperature , Hence this heat is absorbed by water & its temperature rises, Now at equilibrium the water itemperature & temperature g block should be equal. Hence at equilibrium s Heat released by metal = Heat absorbed by water - a metal = + 9 water е се от 2 минат - MALCAL (Tf - T:) = MAR C20 (Tf - T;) on substituting values we get - MALX 0.900 To ) (301-373) 4= 100g x 4,18(T) (301-298)* m = 100 x 4, 18 × 3 (9) = 19.35g. 0.900 x 72 Hence mass of aluminium is 19.359. An

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