HELP A question on vapour pressure

In summary, the conversation is about calculating the molar heat of vaporization of dichloromethane, given its vapor pressure and boiling point. The user also asks for clarification on the definition of boiling. The answer is provided as a rapid vaporization of liquid when it reaches its boiling point.
  • #1
Kudo Shinichi
109
1
HELP!A question on vapour pressure

Homework Statement


The vapor pressure of dichloromethane, CH2Cl2, at 0 degree Celsius is 134 mmHg. The normal boiling point of dichloromethane is 40.0 degree Celsius. Calculate its molar heat of vaporization.


Homework Equations





The Attempt at a Solution



ln(P_2/134)=(Change of H_vapour/8.314)(1/(0+273)-1/(40+273))
I still have two unknown variables...I should find change H_vapour for this question, but I don't know how to figure out P_2

Thank you for helping me.
 
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  • #2


What does boliling mean?
 
  • #3


Borek said:
What does boiling mean?

Boiling (also called ebullition), a type of phase transition, is the rapid vaporization of a liquid, which typically occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding environmental pressure
Source: wikipedia
 
  • #4


Answer to your problem is directly addressed in the quote.
 
  • #5


Thanks. I have got the answer.
 

Related to HELP A question on vapour pressure

1. What is vapour pressure?

Vapour pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system.

2. Why is vapour pressure important?

Vapour pressure is important because it is a measure of how easily a liquid can evaporate into a gas. It also plays a significant role in atmospheric processes and can affect the physical and chemical properties of substances.

3. How is vapour pressure measured?

Vapour pressure can be measured using various techniques, such as the isothermal-isobaric method, the static method, and the dynamic method. These methods involve measuring the pressure of the vapor in equilibrium with its liquid phase at a specific temperature.

4. What factors affect vapour pressure?

The main factors that affect vapour pressure are temperature, intermolecular forces, and the nature of the substance. As temperature increases, vapour pressure also increases. Stronger intermolecular forces result in lower vapour pressure, and substances with higher molecular weights tend to have lower vapour pressures.

5. How does vapour pressure relate to the boiling point of a substance?

Vapour pressure and boiling point are inversely related. As vapour pressure increases, the boiling point decreases. This is because at higher vapour pressures, molecules are more likely to escape from the liquid phase and enter the gas phase, causing the substance to boil at a lower temperature.

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