Calculate Heat of Vaporization and normal boing point (in degree C).?

In summary, the conversation discusses the use of a line equation, y = -4058.7x + 16.10, to solve for the heat of vaporization using pressure measured in kPa instead of atm. The vapor pressure for normal boiling point is also calculated, and the conversation mentions attempting to solve for the temperature using the Clausius-Clapeyron equation, but facing difficulties with the final step.
  • #1
laughingnahga
2
0
Using line equation y = -4058.7x + 16.10 with the experiment pressure measured in kPa instead of atm.

I already solved for heat of vaporization thus:

(-4058.7K)(-8.314 J/mol [itex]\ast[/itex]K)=heat of vaporization = 33444 J/mol = 33.44 kJ/mol.

Also, the vapor pressure for normal boiling point:
(1atm)(101325 Pa/1atm)(1 kPa/1000 Pa)=101.32 kPa

I attempted to solve for T by rearranging the linear form of the Clausius-Clapeyron equation, ln Pvap = (-[itex]\Delta[/itex]H/R)(1/T) + ln [itex]\beta[/itex] into something like this (ln101.32 kPa)(-33444 J/mol [itex]\div[/itex] 8.413 J/mol * K)[itex]\div[/itex]1 - ln16.10 = T but I got something insane like 21857.7 K which even with subtracting 273 to get C is no where near close to the answer choices provided.

Any help with the last part would be greatly appreciated.
 
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  • #2


Telling us what is x and what is y should slightly increase chances that someone will try to understand the problem and what you did.
 
  • #3


I had to turn the assignment in this afternoon so it really doesn't matter at this point.

Thanks anyway...
 

1. What is the definition of heat of vaporization?

The heat of vaporization, also known as the enthalpy of vaporization, is the amount of heat energy required to convert a liquid into a gas at its boiling point. It is a measure of the strength of the intermolecular forces present in a liquid.

2. How is the heat of vaporization calculated?

The heat of vaporization can be calculated using the following formula: Q = m * ΔHvap, where Q is the heat energy, m is the mass of the substance, and ΔHvap is the heat of vaporization. This value can also be found in reference tables for different substances.

3. What factors affect the heat of vaporization?

The heat of vaporization is affected by the strength of intermolecular forces, the type of substance, and the pressure and temperature at which it is being measured. Generally, substances with stronger intermolecular forces will have a higher heat of vaporization.

4. How is the normal boiling point of a substance determined?

The normal boiling point is the temperature at which the vapor pressure of a liquid is equal to the external pressure. It can be determined experimentally by heating the substance until it reaches a constant boiling point, or it can be found in reference tables for different substances.

5. Can the heat of vaporization be negative?

No, the heat of vaporization is a positive value as it represents the energy required to overcome intermolecular forces and change the state of a substance from liquid to gas. A negative value would indicate that heat energy is released during the process.

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