Blog Post 7, Activity 7

Activity 7:

2. Complete the Clicker Questions on Gas Laws in the Teaching Idea “Concept Questions for Chemistry using PhET” posted by Trish Loeblein. Use the PhET Simulation Gas Properties to help answer the questions. On your blog post the answers with your scientific explanations to these questions.

Concept Questions for Chemistry:

1.       There are 2 balloons in a room. They are identical in size and material. One balloon is filled with air and the other balloon is filled with Helium. How does the pressure of the air balloon compare to the pressure of the Helium balloon. The pressure in the air balloon is:

C, greater, because air is more dense than helium and since it is more dense, it has a greater amount of pressure.

 

2.       How does the pressure in the Helium balloon compare to the pressure of the air in the room? The pressure in the Helium balloon is:

A, less, because in order for the balloon to float in the air it has to have less pressure in it than the amount of pressure in the air.

 

3.       How do the number of air molecules in the air balloon compare to the number of He atoms in Helium balloon? The number of air molecules is:

A, less, because air molecules are much bigger than helium atoms, so air molecules take up more space and therefore there cannot be as many as there are helium atoms.

 

4.       How does the average speed of the Helium molecules compare to that of the air molecules? The average speed of the He molecules is:

C, greater, because helium molecules are smaller and are able to fit through the tiny pores in the rubber of a balloon, so they are faster than the big air molecule.

5.       What will happen to the pressure if temp is held constant and the volume is decreased?

B, because when I decreased the volume the pressure increased. The force isn’t changing, but because there is less space for the molecules to move, more collisions are occurring. Also Boyle’s Law states that at constant temperature the volume of a gas inversely proportional to its pressure.

6.       You are flying from Denver to Boston, and you bring along a ½ full bottle of shampoo that was well sealed before you left Denver. You land in Boston and proceed to your hotel. The number of air molecules within the shampoo bottle:

B, stayed the same, because since the shampoo bottle was sealed the change in pressure didn’t directly affect the amount of air molecules inside the bottle.

 

7.       If the walls of the shampoo bottle are strong and rigid so that the bottle has the same shape as before you left, how does the pressure of the air inside the bottle compare to the pressure of the air in Denver?

B, equal to, because since the bottle was from Denver, it has the same amount of pressure as Denver.

 

8.       How does the pressure inside the bottle compare to the pressure of the air in Boston?

A, less than, because the pressure in Denver is lower than it is in Boston, since it is at a higher altitude.

                                                                                                                                     

9.       If you had a water bottle with very soft sides. When you open your suitcase in Boston, the bottle would look:

A, squished, because the pressure is greater in the air outside of the bottle, than it is in the water bottle, so pressure is being exerted on the bottle and because it has soft sides it is squished together.