# A sample of 0.010 mole of oxygen gas is confined at 127°C and 0.80 atmosphere. What would be the pressure of this sample at 27 degrees C and the same volume?

Jan 23, 2017

The pressure will be 0.60 atm.

Since the volume is constant but the pressure and temperature are changing, this is an example of Gay-Lussac's Law:

$\textcolor{b l u e}{\overline{\underline{| \textcolor{w h i t e}{\frac{a}{a}} {P}_{1} / {T}_{1} = {P}_{2} / {T}_{2} \textcolor{w h i t e}{\frac{a}{a}} |}}} \text{ }$

${P}_{1} = \text{0.80 atm}$; ${T}_{1} = \text{(127 + 273.15) K" = "400.15 K}$
${P}_{2} = \text{?}$; $\textcolor{w h i t e}{m m m m} {T}_{2} = \textcolor{w h i t e}{l} \text{(27 + 273.15 K)" = "300.15 K}$
P_2=P_1 × T_2/T_1
${P}_{2} = \text{0.80 atm" × (300.15 color(red)(cancel(color(black)("K"))))/(400.15 color(red)(cancel(color(black)("K")))) = "0.60 atm}$