# Problem: A 36.0–L cylinder of a gas used for calibration of blood gas analyzers in medical laboratories contains 350 g CO2, 805 g O2, and 4,880 g N2. At 25 degrees C, what is the pressure in the cylinder in atmospheres?

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###### FREE Expert Solution

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:

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

Calculate the partial pressure of CO2:

mass CO2 = 350 g

The molar mass of CO2:

CO2     1 x 12.01 g/mol = 12.01 g/mol
2 x 16.00 g/mol = 32.00 g/mol
Total: 44.01 g/mol

moles CO2 = 7.95 mol CO2 ###### Problem Details

A 36.0–L cylinder of a gas used for calibration of blood gas analyzers in medical laboratories contains 350 g CO2, 805 g O2, and 4,880 g N2. At 25 degrees C, what is the pressure in the cylinder in atmospheres?