What is the answer for Pre-lab questions number 1,2,3,4?? In terms of kinetic en

Question

What is the answer for Pre-lab questions number 1,2,3,4??

In terms of kinetic energy (KE), explain why vapor pressure increases with increasing temperature. Provide a definition for the normal boiling point for a liquid. The data you will collect in this lab will be vapor pressures of water at various temperatures. What should be the general trend in the data? Calculate the normal boiling point of a compound that has a vapor pressure of 500 torr at 20 degree C and requires 32 kJ to vaporize 1 mole? Complete the table in Part II of the experiment. The question wants you to determine what volume of each of those liquids contains the same number of molecules as 1 microliter (mu L) of water. List the volumes here as part of your pre lab answers. Rank the compounds in the Part II table according to increasing vapor pressure at constant temperature.

Explanation / Answer

1. The vapor pressure of any liquid in contact with its vapour is the pressure at which vapor is in thermodynamic equilibrium with its liquid phase state. The kinetic energy of the molecules is function of temperature. so higher the kinetic energy of the molecules, more molecules will get into the vapor phase, thereby increasing the vapor pressure.

2. Normal boiling point of liquid is the temperature at which the vapor pressure of the liquid in equlibirum with its vapor becomes equal to the atmospheric pressure.

3. The vapor pressures increases with the increasing temperatures.

4. using Clausius-Clapeyron Equation,

ln (P2 / P2) = (H / R) (1/T1 - 1/T2)

P1 = 760 torr

T1 = ? (unknown)

P2 = 500 torr

T2 = 20+273 = 293 K

H = 32kJ = 32000J

R = 8.314JK-1mol-1

ln (P2 / P2) = (H / R) (1/T1 - 1/T2)

ln(500/760) = 32000/8.314(1/T1 - 1/293)

ln(0.657) = 3848.9(1/T1 - 3.41x10-3)

-0.4187 = 3848.9(1/T1 - 3.41x10-3)

-0.4187/3848.9(1/T1 - 3.41x10-3)

3.41x10-3 - 1.08x10-4 = 1/T1

1/T1 = 3.032 x 10-3

T1 = 329.81 K

So the normal boiling of a compound tha has a vapor pressure of 500 torr at 20 degree celcius and requires 32kj to vaporise one mole is 329.81K

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