Calorimetry: Two Experimental Runs Are Performed to Determine the Calorimetric

question 92

Multiple Choice

Calorimetry: Two experimental runs are performed to determine the calorimetric properties of an alcohol that 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 5.0°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 of water is 4190 J/kg · K. Assume that no heat is exchanged with the styrofoam container and with the surroundings. The heat of fusion of the alcohol is closest to

• A) 5.5 × 10⁴ J/kg.
• B) 6.3 × 10⁴ J/kg.
• C) 7.1 × 10⁴ J/kg.
• D) 7.9 × 10⁴ J/kg.
• E) 8.7 × 10⁴ J/kg.

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