12 g of dry ice (solid CO_2) is placed in a 7000 cm^3 container, then all the air is quickly pumped out and the container sealed. The container is warmed to 0∘C, a temperature at which CO_2 is a gas.

Question

What is the gas pressure? Give your answer in atm.

The gas then undergoes an isothermal compression until the pressure is 2.8 atm , immediately followed by an isobaric compression until the volume is 1000 cm³. What is the final temperature of the gas (in ^∘C)?

Answer 1

moles CO2 = 12 g x 1 mol / 44 g = 0.2727 moles

PV = nRT

P = pressure = ?

V = volume in liters = 7.000 L

n = moles = 0.2727

R = gas constant = 0.0821 Latm/Kmol

T = temperature in Kelvin = 0ºC + 273 = 273K

Solving for P ..

P = nRT / V = (0.2727)(0.0821)(273) / 7.000

P = 0.873 atm