(a) A party store has a tank of helium at a pressure of 6.8 atm in the store, where the temperature is 21°C. If an employee sets it out on the loading dock in the sun, and its temperature rises to 38°C, what will the new pressure be?

(b) Dry ice is frozen carbon dioxide. Suppose you have a piece of dry ice with a mass of 200 grams (a little less than half a pound) which you place into a large deflated bag, which you seal. You then let heat flow into it to turn all the dry ice into gas at a temperature of 20°C. What volume will the bag have expanded to?

(c) A scuba diver 18 m below the surface of a lake breathes out, releasing bubbles into the water. How much do the bubbles expand on their way up? Specifically, for a given bubble, what is the ratio of its volume as it reaches the surface to its volume down where it was created?