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Find the heat content per gram of peanut

  1. Jun 27, 2004 #1
    Can some one help me with these two questions? I am unclear how to do them! Thanks :smile:

    1. A 27.2g peanut is burned in a bomb calorimeter, and the temperature of the surrounding 100g of water rises from 24.25 degrees C to 26.87 degrees C. Given that the calorimeter constant is 2.23kJ/degrees C, find the heat content per gram of peanut.

    2. When 10.0g of water at 90.0 degrees C is added to 100 g of water at 10.0 degrees C in a well-insulated calorimeter, what is the final temperature of the mixture? Assume that all of the heat lost by the hot water is gained by the cold water, and vise versa.
  2. jcsd
  3. Jun 28, 2004 #2


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    H = m*C*[T(final) - T(initial)] where m : mass, C : specific heat capacity, T : temperature
    m*C is refered to as the heat capacity, C', which is specified for the calorimeter ( C' = 2.23kJ/C)

    1. Find the value of C(water) - try Google (if you don't know it). Now you have enough information to find the heat absorbed by the water. Since the calorimeter is in equilibrium with the water, you may assume that it undergoes the same temperature change as the water. So, you can calculate the heat absorbed by the calorimeter. The sum of these two numbers is the total heat released by burning the peanut. Dividing this by the weight of the peanut gives it's calorific value (or heat content per gram).

    2. Heat lost by A = heat gained by B. You know the values of m1, m2, C, T1(initial), T2(initial). When mixed, A and B reach the same final temperature T(final). Plug in all the nhumbers and solve to find T(final).
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