An uninflated balloon full of air has a volume of 300.0 mL and contains 0.0240 mole of air. A 2.00 g piece of dry ice (solid CO₂) is placed in the vessel and sealed. What is the volume of the balloon after the dry ice has vaporized? Assume constant temperature and pressure. Also, assume no change in the initial amount of air.

Question

Quizplus · Accepted Answer

The volume of the balloon increases due to the addition of CO2 gas from the vaporized dry ice. Using the ideal gas law (PV=nRT) and assuming constant temperature and pressure, the volume is directly proportional to the amount of gas. The molar mass of CO2 is 44.01 g/mol, so 2.00 g of CO2 is 2.00 g / 44.01 g/mol = 0.0454 mol. The total moles of gas after the dry ice vaporizes is 0.0240 mol (initial air) + 0.0454 mol (CO2) = 0.0694 mol. Since the initial 0.0240 mol of air occupied 300.0 mL, the volume occupied by 0.0694 mol of gas (maintaining the same conditions) can be found by setting up a proportion: (0.0240 mol / 300.0 mL) = (0.0694 mol / V). Solving for V gives a volume of approximately 869 mL.

An Uninflated Balloon Full of Air Has a Volume of 300.0