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Two identical calorimeters A and B each hold equal amounts of water at 20 degC. A 5 g piece of metal X (specific heat 0.2 cal/g/degC) is dropped into A, and a 5 g piece of metal Y into B. Both metals start at 40 degC. The final equilibrium temperature is 22 degC in A and 23 degC in B. Find the specific heat of metal Y (in cal/g/degC). (Neglect calorimeter heat capacity; assume identical water masses.)

1. 0.1
2. 0.2
3. 0.3
4. 0.4

Correct answer: 0.3

Solution

Dividing the two calorimetry equations eliminates the water mass: c_Y = 0.2*(18/17)*(3/2) approx 0.32, i.e. about 0.3 cal/g/degC.

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