Question

A piece of solid carbon dioxide with a mass of 5.60 g is placed in a 10.0-L vessel that already contains air at 715 torr and 23 ∘C. After the carbon dioxide has totally vaporized, what is the total pressure in the container at 23 ∘C? Express your answer using four significant figures.

Answer 1

Let us calculate the moles of CO2

Moles of CO2 = mass/molar mass CO2

moles CO2 = 5.60 g/ 44.009 g/mol=0.127 Moles

Let us calculate the Moles of ait

P = 715 Torr = 0.9407 atm V = 10 L T = 273 +23 = 296 K

Moles air = pV / RT = 0.9407 atm x 10.0 L / 0.08206 x 297 K = 0.3858 Moles

total moles of Gas ( air + CO2 )= 0.127 + 0.3858 =0.5128

Total pressure = sum of partial pressure

Now calculate the Final pressure

p = nRT/V = 0.5128 x 0.08206 x 296 / 10.0 L=1.245 atm = 947 Torr