[bbco88]

  Here is another one...

A piece of dry ice (solid CO2, d=0.900 g/mL) weighing 16.8 g is placed in a 1.16 L bottle filled with air at 0.99 atm and 438°C. The bottle is capped, and the dry ice changes to gas. What is the final pressure inside the bottle (in atm)?
 
Im not really sure how to go about this question, I thought I could use the formula (P1V1)/(n1T1)=(P2V2)/(n2T2)
P=pressure
V=volume
n= #moles
T= temp
I began by multiply 16.8 g by .900g/mL then multiply by 1000mL to get g/L, then dividing by the mass of CO2 (44.01g) to get 343.558mol/L (Im not even sure if I can plug this into n, because it is the molarity, but I did anways), then I convert C to K to get 711.15 K and then I plugged it into the equation abover, but I know it has to be wrong because my answer is so small, 4.7001*10^-6 and your even left with units atm, mol and K because only L cancels out.  This answer makes no sense so there has to be another way to approach this question, can anyone help thanks!

[Yggdrasil]

For this question, you will need to use the ideal gas law. (P1V1)/(n1T1)=(P2V2)/(n2T2) works only for a gas a one condition turning into a gas at another condition.  If you have a solid or liquid turning into a gas, it won't work because solids and liquids do not obey the ideal gas law.

[bbco88]

so what is a formula I could use for this equation?

[Borek]

http://en.wikipedia.org/wiki/Ideal_gas_law