0.10 Physical properties of gases

Cartesian diver:

The Cartesian diver is named for Rene Descartes (1596-1650), noted French scientist and philosopher. At this station, you will find a plastic soda bottle containing a medicine dropper, water, and air. Squeeze the bottle. 

What happens? Why?

The egg:

 Lightly grease the inside of the neck of a 1 L Erlenmeyer flask with stopcock grease. Clamp the flask onto the stand. Place about 5 mL $H_{2}O$ in the flask and gently warm it with a Bunsen burner until the water vaporizes. Do not boil the water to dryness. Meanwhile, prepare an ice water bath in an evaporating dish. While the flask is warm, seat the egg, narrow end down, in the mouth of the flask. Unclamp the flask, allow to cool slightly sitting on the bench and then immerse it in the ice water. (Read the safety notes above to avoid breaking the flask)

Can you get the egg back out again?

Assuming that the flask reaches the maximum vacuum (minimum pressure) possible before the egg is drawn into the flask, calculate the minimum pressure reached in the flask.

Expanding balloon:

Partially inflate a balloon. Place the balloon inside the vacuum chamber and close the chamber with the black rubber circle and the top of the chamber carefully centered on the base (A partially inflated balloon may already be in the dessicator). Close the needle valve (at the bottom of the black rubber tubing) by turning it clockwise. Turn the stopcock to the up position to connect the chamber to the vacuum pump. What happens? To open the chamber, turn the stopcock to the left position and open the needle valve.

Bonus 2 points: 

1pt to name a real life example of the physical properties of gases at work

1pt for a good explanation of how and why it works according to what you have learned in the lab.

Pre-lab: physical properties of gases

(total 10 points)

Hopefully here for the Pre-Lab

Note: In preparing this report you are free to use references and consult with others. However, you may not copy from other students’work (including your laboratory partner) or misrepresent your own data (see honor code).

Name(Print then sign): ___________________________________________________

Lab Day: ___________________Section: ________TA__________________________

• Define diffusion and write down equation for diffusion rate:
• Write equation for ideal gas law and describe each term.
• Define Charles’, Boyle’s, and Avogadro’s law:
• Fill the blanks (which law applies):
• When temperature increases in a close balloon the volume ________.

_______Law

• When pressure is applied to a close balloon the volume _________.

_______Law

• When temperature decreases in a close balloon the pressure _________.

_______Law

Report: physical properties of gases

(total 80 points)

Hopefully here for the Report

Note: In preparing this report you are free to use references and consult with others. However, you may not copy from other students’work (including your laboratory partner) or misrepresent your own data (see honor code).

1. Diffusion:

At the end of your report attach the graphs of each trial.

The average of the rates for the three trials is----------------

The root mean square speed of carvone molecules at 25C is

------------------------------------------------------------------------

Compare the result with the diffusion rate you measured. If they are significantly different, offer an explanation.

Would the diffusion take place faster in a vacuum?

2. Gas Laws in a Soda Can:

Describe what happens.

Explain why it happens. You may repeat this experiment using a second soda can if you wish.

Why is it necessary to invert the can in the water?

What would happen if a rigid container were used?

3. Balloon in liquid nitrogen:

The estimated size of the balloon in liters is--------------

What is the pressure inside the balloon before it is placed in the liquid nitrogen?

What is the pressure inside the balloon after it is placed in the liquid nitrogen?

Use the ideal gas law to calculate the percent change in volume expected on going from room temperature to liquid nitrogen temperature.

Is the volume of the cold balloon consistent with what you calculated, or is it larger or smaller?

Suggest an explanation for your observation. Explain all of your observations in detail using the kinetic molecular theory of gases.

How does the liquid nitrogen cool the gas in the balloon?

4. Balloon in a flask:

 What was the effect as the flask cools?

Can you get the balloon back out again?

5. Kissell's tygon tube:

What happens?

Why?

6. Cartesian diver:

What happens?

Why?

7. The Egg:

What happens?

Why?

Can you get the egg back out again?

The minimum pressure reached in the flask is -------------------

8. Expanding balloon:

 What happens?

 Moore's bonus 2 points: 

1pt to name a real life example of the physical properties of gases at work

1pt for a good explanation of how and why it works according to what you have learned in the lab.