1. SCH3U – Quiz # 4

2. A balloon that contains 31.2 L of helium gas, at 98 kPa, is released and rises into the atmosphere. What is the new pressure, in atm, of the balloon when it eventually fills up to a new volume of 129.8 L?

3. What would be the new volume if the temperature on 150 mL of a certain gas is changed from 40 o C to -5 o C?

4. When you walk up a mountain, your ears feel strange. What are you feeling and WHY?

5. Why is it a terrible idea, when deep-sea diving, to rise back to the surface at a quick rate?

6. A balloon that contains 31.2 L of helium gas, at 98 kPa, is released and rises into the atmosphere. What is the new pressure, in atm, of the balloon when it eventually fills up to a new volume of 129.8 L? P 1 V 1 = P 2 V 2 (98 kPa)(31.2 L) = P 2 (129.8 L) P 2 = 23.6 kPa 1 atm = x 101.3 kPa 98 kPa x = 0.97 atm

7. What would be the new volume if the temperature on 150 mL of a certain gas is changed from 40 o C to -5 o C? V1 = V2 T1 T2 150 mL = V2 313 K 268 K V2 = 128 mL

8. When you walk up a mountain, your ears feel strange. What are you feeling and WHY? Your ears may pop or your eardrums may feel as if it’s expanding (which it is!) Boyle’s Law says that as pressure ↓, volume ↑ Pressure on ground is 1 atm. As you move upwards into the atmosphere, the pressure ↓ (air is less dense due to particles being further apart). The ↓ in pressure causes an ↑ in volume!

9. Why is it a terrible idea, when deep-sea diving, to rise back to the surface at a quick rate? As previously stated, Boyle’s Law says as pressure ↑, volume ↓ When deep-sea diving, the pressure is very great due to the force of gravity pushing air+water on top of you. This pressure ↑ causes the volume of your body’s organs (eg. Lungs, liver) to ↓ When you swim back up, the pressure ↓, causing your body’s organ to ↑ in volume. But you have to go slowly. If you ascend too fast, the gases in your blood will burst out into solution, like opening up a can of pop. You must acclimatize at certain levels before continuing to ascend. = THE BENDS