posted by mel .
hot-air balloon is filled with air at a volume of 3.64 x 10^3 m^3 at 745 torr at 39C. the air in balloon is heated to 60C, causing balloon to expand to a volume of 4.50x 10^3 m^3. what is the ratio of the number of moles of the air in heated balloon to original number of moles of air in balloon? (hint: openings in balloon allow air to flow in and out, thus pressure in balloon is always same as atmosphere.
I would use PV = nRT
Use any number for P since it is constant. I would choose 1 atmosphere. I would change m^3 to liters although that probably isn't necessary since the problem asks for a ratio. Use R = 0.08205, convert T to Kelvin (K = C + 273). Calculate n for each set of parameters and take the ratio of the two values.