Fri December 23, 2011 By: Aparna Tomar

100 g of water is heated from 30ºC to 50ºC. Ignoring the slight expansion of the water, the change in its internal energy is (specific heat of water is 4184 J/Kg/K)

Expert Reply
Sun December 25, 2011
From first law of thermodynamics,
        dE= dq + dw
We also know that, dQ=m.s.dT
 where, s=specific heat of the substance
           m=mass of substance
          dT=Temperature change
In above question ,dW=0 because we do not have to consider the change in energy due to expansion of water.Thus the required formula becomes
Now dQ=(100 x 10-3 ) x (4184) x(323-303) J =4184 x 2= 8368 J
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