1. The problem statement, all variables and given/known data Imagine that 9.9 g of liquid helium, initially at 4.20 K, evaporate into an empty balloon that is kept at 1.00-atm pressure. What is the volume of the ballonat the following? (a) 23.0 K (b) 299 K 2. Relevant equations PV=nRT 3. The attempt at a solution I converted th 9.9g of Helium to number of moles. n=2.473mol and used that to find the volume at T=23 and T=299, but it isn't right. steps 1) n=9.9g=(9.9g/(4.003g/mol))=2.47314 mol R=8.314472 <-- gas constant P= 1 as stated in the problem V@ T=23 : V=(nRT)/P -> (2.47314*8.314472*23)/1 --> V=472.9466 L V@ T=299 : V=(nRT)/P -> (2.47314*8.314472*299)/1 --> V=6148.30591237 L I'm guessing I need to do something with T=4.2 first, but I'm not sure what.