# Lab 9.docx - Enthalpy and Specific Heat pre-lab Questions...

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pre-lab Questions 1 . When 3.0 kg of water is warmed from 10 °C to 80 °C, how much heat energy is needed? The specific heat of water is 4.184J/g o C. Show the calculation works . Q= C x M x T 3kg= 3000g 4.18j/gc x 3000g x 70c = 877800 Joules= 877.8 Kj 877.8 Kj of energy is required to warm 3kg of water from 10C to 80C 2. A calorimeter contains 100 g of water at 39.8 ºC. A 8.23 g object at 50 ºC is placed inside the calorimeter. When equilibrium has been reached, the new temperature of the water and metal object is 40 ºC. Calculate the specific heat of the metal. The specific heat of water is 4.184J/g o C. Show the calculation works. 100g *4.18*(40-39.8)˚C = 8.23*C m*(50-40)˚C =1.02J/g Enthalpy and Specific Heat
experiment 1: determination of specific heat of a metal Data Sheet Table 2: Mass Mass (g ( Water 49.5g Unknown Metal Strip 11.8g Table 3: Specific Heat Data Time (minutes ( Temperature (°C ( Trial 1 Trial 2 Trial 3 Initial 23.3 C 24.1 C 23.5 C 5 minutes 23.4 C 24.4 C 25.0 C 6 minutes 23.4 C 24.4 C 24.9 C 7 minutes 23.5 C 24.4 C 24.9 C 8 minutes 23.5 C 24.4 C 24.9. C 9 minutes 23.5 C 24.4 C 24.9 C 10 minutes 23.5 C 24.4 C 24.9 Specific Heat Capacity of the Unknown Metal 1.77 1.18 0.25 Average Specific Heat Capacity of the Unknown Metal 1.066 Post-Lab Questions 1 . Calculate the specific heat capacity of the unknown metal for all three trials. The specific heat of water is 4.184J/g o C. Show the calculation works. Hint: initial temperature of the unknown metal is 100 o C .