Experiment 5: Vapor Pressure And Heat Of Vaporization Of Liquids

Question 1

How can the movement of molecules of liquids and solids (at nonzero temperatures) be described?

Answer 1

Molecules of liquids and solids (at nonzero temperatures) are vibrating with kinetic energy proportional to their temperature. Molecules that lie on the surface of a liquid or a solid feel a net “kick” from below by other vibrating molecules. Some of these surface molecules get kicked so hard from below that they are knocked off the surface of the liquid (or solid) into the air. Once there, the molecule becomes a gas molecule and is no longer associated with the liquid (or solid).

Question 2

In this experiment, what relationships are going to be investigated?

Answer 2

Relationship between Vapor Pressure and Temperature

Question 3

You will use a _____ to determine the heat of vaporization of an unknown liquid.

Answer 3

Linear Graph

Question 4

What will be graphed on the Y-Axis?

Answer 4

LN VP. YLN

Question 5

What will be graphed on the x-axis?

Answer 5

1/T

Question 6

What is the slope of the graph equivalent to?

Answer 6

-DELTA H VAP/R

Question 7

What is the partial pressure of the vapor exerted above the surface of the liquid?

Answer 7

Vapor Pressure

Question 8

What is the units of R in this experiment?

Answer 8

J/MolK

Question 9

What must be subtracted from each pressure measurement in order to determine the vapor pressure of the liquid?

Answer 9

Atmospheric Pressure

Question 10

What is the temperature at which the vapor pressure of a liquid is equal to the external pressure of the atmosphere above the liquid?

Answer 10

Boiling Point

Question 11

What is an important formula to remember regarding Q water and Q metal?

Answer 11

Q Water= (-) Q Metal