The chlorofluorocarbon refrigerant trichlorofluoromethane, CCl3F, has Pvap = 100.0 mm Hg at -23 °C and ΔHvap= 24.77 kJ>mol.(b) What is ΔSvap for trichlorofluoromethane?

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Step 1: Understand that the change in entropy of vaporization (ΔSvap) can be calculated using the Clausius-Clapeyron equation, which is ΔHvap = ΔSvap * T, where T is the temperature in Kelvin.

Step 2: Convert the given temperature from Celsius to Kelvin. The conversion formula is T(K) = T(°C) + 273.15.

Step 3: Convert the given ΔHvap from kJ/mol to J/mol by multiplying by 1000, because 1 kJ = 1000 J.

Step 4: Rearrange the Clausius-Clapeyron equation to solve for ΔSvap. The rearranged equation is ΔSvap = ΔHvap / T.

Step 5: Substitute the values of ΔHvap and T into the rearranged equation to calculate ΔSvap.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Vaporization and Enthalpy of Vaporization (ΔHvap)

Vaporization is the process by which a liquid turns into vapor. The enthalpy of vaporization (ΔHvap) is the amount of energy required to convert one mole of a liquid into vapor at constant temperature and pressure. In this case, ΔHvap for trichlorofluoromethane is given as 24.77 kJ/mol, indicating the energy needed for its phase change from liquid to gas.

Entropy (ΔSvap)

Entropy is a measure of the disorder or randomness in a system. The change in entropy during vaporization (ΔSvap) can be calculated using the relationship between enthalpy and temperature. It reflects how much the disorder increases when a substance transitions from a liquid to a gas, which is crucial for understanding thermodynamic processes.

Clausius-Clapeyron Equation

The Clausius-Clapeyron equation relates the vapor pressure of a substance to its temperature and enthalpy of vaporization. It can be used to derive the change in entropy during vaporization by the formula ΔSvap = ΔHvap / T, where T is the absolute temperature in Kelvin. This equation is essential for calculating ΔSvap for trichlorofluoromethane using the provided values.

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