Ideal gas law question. How do I do this problem?

a) Assume that air pressure is 1.00 atm and the air temperature is 15.4o C. If the abolute zero apparatus is open to the air, how many moles of air will it hold?

moles

Without the volume of the sphere there is no way to determine the number of moles of gas. The use of this device doesn't require knowing the volume. All you care about is that it is constant. Therefore, you are using Amontons's law, P1/T1= P2/T2. You pump it up to some pressure above atmospheric pressure, determine the actual pressure in the sphere (gauge pressure + atmospheric pressure) when the sphere is sitting in a large beaker of water at a particular temperature. You do this for six or eight temperatures and plot P vs T. Extrapolate to the x-axis and it should cross at -273 or nearby.

b) Suppose now that the apparatus is sealed, and the temperature rises to 43.0o C. Find the pressure inside the apparatus now.

P1/T1 = P2/T2 ...... Amonton's law

P2 = P1T2 / T1 ..... solve for P2

P2 = 1.00 atm x 316K / 288.6K ..... T must be in Kelvins

P2 = 1.09 atm ....... answer is good three significant digits

T temperature to be measured on kelvin scale.. i.e. 19+273 ok and no of moles.. weight divided by using molecular weight fee of R 2 b chosen accordin to the contraptions used for pressur en quantity.. if u use atm-l then the fee of R is 0.0821 if u use pascal-m^3 fee is 8.314 and for calculation of heat or power in energy, fee of R shud be approximated to 2