A sample of O2 under 2.00 atm occupies 500 ml at 25.0˚C. What pressure will the sample have at 0.0˚C ?

Jul 2, 2014

In this question we will use the ideal gas equation.

${P}_{1}$ x ${V}_{1}$ / ${T}_{1}$ = ${P}_{2}$ x ${V}_{2}$ / ${T}_{2}$

${P}_{1}$ = 2 atm
${V}_{1}$ = 500 mL
${T}_{1}$ = 25 + 273 = 298 K

${P}_{2}$ = ?
${V}_{2}$ = 500 mL
${T}_{2}$ = 0 + 273 = 273 K

substituting values;

2 atm x 500 mL / 298 K = ${P}_{2}$ x 500 mL / 273

rearranging we get,

1000 atm mL x 273 K / 500 mL x 298 K = ${P}_{2}$

${P}_{2}$ = 1.83 atm.