In the laboratory a \"coffee cup\" calorimeter, or constant pressure calorimeter

Question

In the laboratory a "coffee cup" calorimeter, or constant pressure calorimeter, is frequently used to determine the specific heat of a solid, or to measure the energy of a solution phase reaction. Stirring rod Since the cup itself can absorb energy, a separate experiment is needed to determine the heat capacity of the calorimeter. This is known as calibrating the calorimeter and the value determined is called the calorimeter constant. One way to do this is to use a common metal of known heat capacity. In the laboratory a student heats 93.74 grams of zinc to 99.25 °C and then drops it into a cup containing 84.57 grams of water at 22.42 °C. She measures the final temperature to be Water 29.55 °C. Metal sample Using the accepted value for the specific heat of zine (See the References tool), calculate the calorimeter constant. Calorimeter Constant- J/OC

Explanation / Answer

specific heat of zinc= 0.39 j/gm.deg.c, specific heat of water= 4.184 J/gm.deg.c

here heat lost by zinc = heat gained by water+ heat gained by calorimeter

mass of zinc* specific heat of zinc*temperature change of zinc= mass of water* specific heat of water* temperature change of water+heat capacity of calorimeter* change in temperature

93.74*0.39*(99.25-29.55)= 84.57*4.184*(29.55-22.42)+heat capacity of calorimeter* (29.55-22.42)

2548= 2523+7.13*heat capacity of calorimeter.

heat capacity of calorimeter= 3.51 J/deg.c

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