Chemistry
posted by Amanda .
If 16.5 g of oxygen gas is required to inflate a balloon to a certain Volume at 26.5 degrees Celcius, what mass of oxygen gas is required to inflate the same balloon to the same volume and pressure at 10.0 degrees Celcius?

Note the correct spelling of celsius.
I would do the following although it may be the long way around.
Use PV = nRT. Make up a number for V(say an easy number like 1 L) and solve for P. Then substitute that P and the new T and solve for n = number of moles for the new filling. Then n = grams/molar mass and solve for grams. I think the answer is close to 17 grams but that is approximate.