Question

A piece of dry ice (solid carbon dioxide) with a mass of 5.50 g is placed in a 10.0-l vessel that already contains air at 705 torr and 24 °c. after the carbon dioxide has totally sublimed, what is the partial pressure of the resultant co2 gas, and the total pressure in the container at 24 °c?

Answer 1

 The partial  pressure  of  resultant CO₂  gas  is 231.5 torr

The total  pressure = 936.5 torr

 calculation

The partial  for CO₂  is calculated using  the ideal gas equation

That is PV=nRT

where;

p(pressure = ?

V( volume) = 10.0 l

n(number of moles) = mass÷molar mass

from periodic table the molar mass of CO₂ = 12 + (16 x2)  = 44 g/mol

moles = 5.50 g÷44 g/mol =0.125 moles

R( gas constant) = 62.36 torr

T ( temperature) = 24°c into Kelvin = 24 +273 =297 K

make P the subject  of the formula by diving both side of equation by V

P  =nRT/V

P  ={( 0.125 moles x 62.36 L.torr/Mol.K  x297 K)  / 10 L}  = 231.5 torr

Total pressure = partial pressure for air + partial  pressure for CO₂

= 705 torr + 231.5 torr =936.5 torr