We’re being asked to **calculate for the ****total pressure in the flask**.

We’re going to calculate the pressure of each gas first using the **ideal gas equation**:

$\overline{){\mathbf{PV}}{\mathbf{=}}{\mathbf{nRT}}}$

P = pressure, atm

V = volume, L

n = moles, mol

R = gas constant = 0.08206 (L·atm)/(mol·K)

T = temperature, K

*Rearranging the ideal gas equation:*

$\frac{\mathbf{P}\overline{)\mathbf{V}}}{\overline{)\mathbf{V}}}\mathbf{=}\frac{\mathbf{nRT}}{\mathbf{V}}\phantom{\rule{0ex}{0ex}}\overline{){\mathbf{P}}{\mathbf{=}}\frac{\mathbf{nRT}}{\mathbf{V}}}$

A 1.25 -g sample of dry ice is added to a 765 -mL flask containing nitrogen gas at a temperature of 25.0 ^{o}C and a pressure of 735 mm Hg . The dry ice is allowed to sublime (convert from solid to gas) and the mixture is allowed to return to 25.0 ^{o}C.

What is the total pressure in the flask?