Activity 7: Gases

1.       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 you scientific explanations to these questions.

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?

                                                               i.      C: Greater, the air is denser which causes more 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?

                                                               i.      A: Less, There is less pressure in the helium balloons.

3)      How does 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?

                                                               i.      A: Less, Air molecules take up more space, it takes less air molecules to fill up space than helium molecules.

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?

                                                               i.      C: Greater, The helium molecules are smaller which causes them to move faster.  

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

                                                               i.      B: Pressure goes up because more collisions are happening, but same force per collision, Boyle’s Law states that at constant temp. the volume of a gas is 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?

                                                               i.      B: Has stayed the same, the bottle was sealed which caused it not to affect the number of molecules in 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?

                                                               i.      B: Equal to, the air pressure will remain the same.

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

                                                               i.      A: Less than, The pressure in Denver is lower than in Boston, Denver has 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?

                                                               i.      A: Squished, The pressure in the air is greater than the pressure in the bottle.