In the laboratory a \"coffee cup\" calorimeter , or constant pressure calorimete
ID: 913531 • Letter: I
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.
A chunk of gold weighing 19.09 grams and originally at 97.99 °C is dropped into an insulated cup containing 81.00 grams of water at 22.78 °C.
The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.90 J/°C.
Using the accepted value for the specific heat of gold, .129 J/goC, calculate the final temperature of the water. Assume that no heat is lost to the surroundings.
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.
A chunk of gold weighing 19.09 grams and originally at 97.99 °C is dropped into an insulated cup containing 81.00 grams of water at 22.78 °C.
The heat capacity of the calorimeter (sometimes referred to as the calorimeter constant) was determined in a separate experiment to be 1.90 J/°C.
Using the accepted value for the specific heat of gold, .129 J/goC, calculate the final temperature of the water. Assume that no heat is lost to the surroundings.
Explanation / Answer
mass of gold =mgold 19.09 g
Initial temperature =T1 = 97.99 °C
mass of water = 81 g
Water Initial temperature = T1 = 22.78 °C
Specific heat capacity of glod = Cgold = 0.129 J/g.°C
Specific heat capacity of water= CH2O = 4.18 J/g.°C
specific heat capacity of cup = C cup = 1.90 J/°C
Final temperature of gold = water = cup = T2
Heat lost by the gold = heat gained by the water + heat gained by the calorimeter
Qgold = QH2O + Qcalorimeter
mC(T1-T2) = mC(T2-T1) + C(T2-T1)
19.09(0.129)(97.99-T2) = 81(4.18)(T2-22.78)* (1.90)(T2-22.78)
2.463(97.99-T2) = 338.58(T2-22.78)2 * (1.90)
2.463(97.99-T2) = 643.3(T2-22.78)2
97.99-T2 = 261.2(T2-22.78)2
By solving this T2 = 23.3°C
So final temperature of water = 23.3 °C
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