The fluorocarbon compound C2Cl3F3 has a normal boiling point of 47.6 °C. The specific heats of C2Cl3F3(l) and C2Cl3F3(g) are 0.91 and 0.67 J/g-K, respectively. The heat of vaporization for the compound is 27.49 kJ/mol. Calculate the heat required to convert 35.0 g of C2Cl3F3 from a liquid at 10.00 °C to a gas at 105.00 °C.

Verified step by step guidance

Step 1: Calculate the heat required to raise the temperature of the liquid C2Cl3F3 from 10.00 °C to its boiling point at 47.6 °C using the formula q = m * c * ΔT, where m is the mass, c is the specific heat capacity of the liquid, and ΔT is the change in temperature.

Step 2: Calculate the heat required for the phase change from liquid to gas at the boiling point using the formula q = n * ΔHvap, where n is the number of moles of C2Cl3F3 and ΔHvap is the heat of vaporization.

Step 3: Calculate the heat required to raise the temperature of the gaseous C2Cl3F3 from the boiling point at 47.6 °C to 105.00 °C using the formula q = m * c * ΔT, where m is the mass, c is the specific heat capacity of the gas, and ΔT is the change in temperature.

Step 4: Convert the mass of C2Cl3F3 to moles using its molar mass to use in the phase change calculation.

Step 5: Sum the heats calculated in Steps 1, 2, and 3 to find the total heat required for the entire process.

Key Concepts

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

Heat Transfer and Specific Heat

Specific heat is the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. In this problem, the specific heats of C2Cl3F3 in both liquid and gas phases are crucial for calculating the heat required to change the temperature of the substance in each phase. The formula used is Q = mcΔT, where Q is the heat absorbed or released, m is the mass, c is the specific heat, and ΔT is the change in temperature.

Phase Change and Heat of Vaporization

The heat of vaporization is the amount of energy needed to convert a unit mass of a substance from liquid to gas at its boiling point. For C2Cl3F3, this value is given as 27.49 kJ/mol. During the phase change from liquid to gas, this energy must be accounted for in the total heat calculation, as it represents the energy required to overcome intermolecular forces.

Thermodynamic Calculations

Thermodynamic calculations involve determining the heat transfer associated with physical changes, such as temperature changes and phase transitions. In this problem, the total heat required is the sum of the heat needed to raise the temperature of the liquid to its boiling point, the heat of vaporization to convert it to gas, and the heat needed to raise the temperature of the gas to the final temperature. Each step requires careful application of the relevant formulas and constants.

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Textbook Question

For many years drinking water has been cooled in hot climates by evaporating it from the surfaces of canvas bags or porous clay pots. How many grams of water can be cooled from 35 to 20 °C by the evaporation of 60 g of water? (The heat of vaporization of water in this temperature range is 2.4 kJ/g. The specific heat of water is 4.18 J/g-K).

Textbook Question

The critical temperatures and pressures of a series of halogenated methanes are as follows:

(a) List the intermolecular forces that occur for each compound.

Textbook Question

The critical temperatures and pressures of a series of halogenated methanes are as follows: (c) Predict the critical temperature and pressure for CCl4 based on the trends in this table. Look up the experimentally determined critical temperatures and pressures for CCl4, using a source such as the CRC Handbook of Chemistry and Physics, and suggest a reason for any discrepancies.