The Role of Enthalpy of Vaporization

Oct 13, 2025 by miodeya.com 32 views

Introduction

Water is a vital component of our planet, and its condensation process is a crucial aspect of the Earth's water cycle. When water vapor in the atmosphere condenses into liquid water, it releases heat energy into the environment. This process is an essential part of the Earth's climate system, and understanding the thermodynamics behind it is crucial for various scientific and engineering applications.

The Role of Enthalpy of Vaporization

The enthalpy of vaporization, denoted by $\Delta H_{\text{vap}}$ , is the energy required to change a substance from its liquid state to its gaseous state at a given temperature. In the case of water, the enthalpy of vaporization is 40.7 kJ/mol. This value represents the energy required to vaporize one mole of water at its boiling point.

Calculating the Quantity of Heat Released

When 27.9 g of water condenses, the quantity of heat released can be calculated using the formula $q = n \Delta H$ . However, we need to determine the number of moles of water that condenses. To do this, we can use the molar mass of water, which is 18.02 g/mol.

# Define the mass of water that condenses
mass_water = 27.9  # g

# Define the molar mass of water
molar_mass_water = 18.02  # g/mol

# Calculate the number of moles of water that condenses
n = mass_water / molar_mass_water

Calculating the Quantity of Heat Released

Now that we have the number of moles of water that condenses, we can calculate the quantity of heat released using the formula $q = n \Delta H$ .

# Define the enthalpy of vaporization of water
delta_h_vap = 40.7  # kJ/mol

# Calculate the quantity of heat released
q = n * delta_h_vap

Solving for the Quantity of Heat Released

By substituting the values of $n$ and $\Delta H_{\text{vap}}$ into the formula $q = n \Delta H$ , we can solve for the quantity of heat released.

# Calculate the number of moles of water that condenses
n = 27.9 / 18.02
n = 1.543

# Calculate the quantity of heat released
q = 1.543 * 40.7
q = 62.73

Rounding the Answer

Since the answer choices are given to three significant figures, we can round our answer to three significant figures.

# Round the answer to three significant figures
q = round(q, 3)
q = 62.7

Conclusion

In conclusion, when 27.9 g of water condenses, the quantity of heat released is 62.7 kJ. This value represents the energy released into the environment as the water condenses from its gaseous state to its liquid state.

Answer

Introduction

In our previous article, we explored the condensation process of water and calculated the quantity of heat released when 27.9 g of water condenses. In this article, we will answer some frequently asked questions related to the condensation process of water.

Q: What is the difference between condensation and evaporation?

A: Condensation is the process by which water vapor in the atmosphere changes back into liquid water. Evaporation, on the other hand, is the process by which liquid water changes into water vapor. In other words, condensation is the opposite of evaporation.

Q: What is the role of enthalpy of vaporization in the condensation process?

A: The enthalpy of vaporization, denoted by $\Delta H_{\text{vap}}$ , is the energy required to change a substance from its liquid state to its gaseous state at a given temperature. In the case of water, the enthalpy of vaporization is 40.7 kJ/mol. This value represents the energy required to vaporize one mole of water at its boiling point.

Q: How is the quantity of heat released calculated during condensation?

A: The quantity of heat released during condensation can be calculated using the formula $q = n \Delta H$ , where $n$ is the number of moles of water that condenses and $\Delta H$ is the enthalpy of vaporization.

Q: What is the significance of the molar mass of water in calculating the quantity of heat released?

A: The molar mass of water is 18.02 g/mol. This value is used to calculate the number of moles of water that condenses, which is then used to calculate the quantity of heat released.

Q: Can you provide an example of how to calculate the quantity of heat released during condensation?

A: Let's say we have 27.9 g of water that condenses. To calculate the quantity of heat released, we can use the formula $q = n \Delta H$ . First, we need to calculate the number of moles of water that condenses using the molar mass of water.

# Define the mass of water that condenses
mass_water = 27.9  # g

# Define the molar mass of water
molar_mass_water = 18.02  # g/mol

# Calculate the number of moles of water that condenses
n = mass_water / molar_mass_water

Next, we can calculate the quantity of heat released using the formula $q = n \Delta H$ .

# Define the enthalpy of vaporization of water
delta_h_vap = 40.7  # kJ/mol

# Calculate the quantity of heat released
q = n * delta_h_vap

Q: What is the relationship between the quantity of heat released and the temperature of the surroundings?

A: The quantity of heat released during condensation is related to the temperature of the surroundings. If the temperature of the surroundings is higher than the boiling point of water, the quantity of heat released will be greater. Conversely, if the temperature of the surroundings is lower than the boiling point of water, the quantity of heat released will be smaller.

Conclusion

In conclusion, the condensation process of water is an important aspect of the Earth's water cycle. Understanding the thermodynamics behind this process is crucial for various scientific and engineering applications. We hope that this Q&A article has provided you with a better understanding of the condensation process of water.

Frequently Asked Questions

What is the difference between condensation and evaporation?
What is the role of enthalpy of vaporization in the condensation process?
How is the quantity of heat released calculated during condensation?
What is the significance of the molar mass of water in calculating the quantity of heat released?
Can you provide an example of how to calculate the quantity of heat released during condensation?
What is the relationship between the quantity of heat released and the temperature of the surroundings?

Answers

Condensation is the process by which water vapor in the atmosphere changes back into liquid water. Evaporation, on the other hand, is the process by which liquid water changes into water vapor.
The enthalpy of vaporization, denoted by $\Delta H_{\text{vap}}$ , is the energy required to change a substance from its liquid state to its gaseous state at a given temperature.
The quantity of heat released during condensation can be calculated using the formula $q = n \Delta H$ , where $n$ is the number of moles of water that condenses and $\Delta H$ is the enthalpy of vaporization.
The molar mass of water is 18.02 g/mol, which is used to calculate the number of moles of water that condenses.
The quantity of heat released during condensation can be calculated using the formula $q = n \Delta H$ , where $n$ is the number of moles of water that condenses and $\Delta H$ is the enthalpy of vaporization.
The quantity of heat released during condensation is related to the temperature of the surroundings. If the temperature of the surroundings is higher than the boiling point of water, the quantity of heat released will be greater. Conversely, if the temperature of the surroundings is lower than the boiling point of water, the quantity of heat released will be smaller.