Situation. Two experimental runs are performed to determine the calorimetric pro
ID: 1568382 • Letter: S
Question
Situation.
Two experimental runs are performed to determine the calorimetric properties of an alcohol which has a melting point of -10°C. In the first run, a 200 g cube of frozen alcohol, at the melting point, is added to 300 g of water at 20°C in a styrofoam container. When thermal equilibrium is reached, the alcohol-water solution is at a temperature of 5°C. In the second run, an identical cube of alcohol is added to 500 g of water at 20°C and the temperature at thermal equilibrium is 10°C. The specific heat capacity of water is 4190 J/kg K. Assume the styrofoam container and the surroundings do not partake in the heat exchange.
In the situation above, the specific heat capacity of the alcohol is closest to:
2500 J/kg K 2100 J/kg K 1700 J/kg K 2300 J/kg K 1900 J/kg KExplanation / Answer
1st case:
energy released by water = 300 x 4.19 x (20 - 5)
= 18855 J
energy absorbed by cube = (200 Lf) + (200 x C x 15)
= 200 Lf + 3000C
200 Lf + 3000C = 18855 ...........(i)
2nd case:
energy released by water = 500 x4.19 x 10 = 20950
energy absorbed by cube = (200 Lf) + (200 x C x 20 )
200 Lf + 4000C = 20950 ..... (ii)
(ii) - (i) =>
1000C = 2095
C = 2.095 J/g K
OR C = 2095 J / kg K
Ans : 2100 J/kg K