Chapter 13 study guide (labs):
1. How does the volume of air in a scuba diver’s lungs change when they descending into the
water? Ascending? Why?
Descending – volume decreases because pressure is increasing
Ascending – volume increases because pressure in decreasing
2. What are the symptoms, causes, treatments and prevention for nitrogen narcosis, oxygen
toxicity and decompression sickness? (matching section on test)
Nitrogen narcosis – interferes with ability to think rationally, caused by inhaling nitrogen
under pressure, prevention includes staying within safe depth limits, treatment is to ascend to
a safe depth
Oxygen toxicity – burning in lungs and esophagus, damage to tissue due to free radicals from
too much oxygen, caused by breathing in oxygen under pressure, prevention and treatment
same as for nitrogen narcosis
Decompression sickness – caused by ascending to quickly, nitrogen comes out of solution too
fast causing large air bubbles to form in the blood which causes muscle pain a few days after
the dive and can lead to embolisms, treatment would involve a hyperbaric chamber (high
pressure to force nitrogen back into solution and then pressure is slowly decreased allowing
the nitrogen to come out of solution in smaller amounts), prevention would be to ascend
slowly
3. Why did the can crush when it was placed in cold water? What gas law is this?
Cold temp condensed the air and the can collapsed. Charles’s law
4. Why did the dropper sink when the bottle was squeezed? What gas law is this?
Increasing the pressure decreased the volume of air in the dropper causing it to sink. Boyle’s
law
5. What caused the kernels to pop? What gas law is this?
Increased pressure due to an increase in temperature. (water vapor) Gay-Lussac’s law
6. Why don’t all the kernels pop?
May not contain moisture – no pressure builds. They are dehydrated.
7.
Why is oil a better choice than water for popping corn?
It has a higher boiling point, can reach a higher temp causing more pressure to build.
8. What is a barometer?
A device that measures atmospheric pressure.
9. How does a mercury barometer work? Our barometers?
Air presses down on the mercury forcing it to move up a tube.
Air presses down on the balloon causing the straw to rise. Low pressure – balloon inflates and
straw drops.
10. How does air pressure change with weather? Why? What law is this?
Cold, dry air, clear skies – N2 and O2 condense = decrease in volume = increase in pressure
Cloudy, more humid air – H2O in air decreases the density because it is lighter than N2 and O2,
causes the N2 and O2 molecules to spread out (expand) = increase in volume = decrease in
pressure
Boyle’s law
11. What is pressure?
Force per unit area