Question

2. A 8.34-g piece of solid CO
2
(dry ice) is allowed to sublime in a balloon. The final volume of the
balloon is 1.00 L at 299 K. What is the pressure of the gas?
A) 2.94 atm
B) 2.05 × 10^2atm
C) 4.65 atm
D) 0.215 atm
E) none of these

Answer 1

Answer – In this problem we are given mass of CO₂ = 8.34 g

Final Volume = 1.00 L, T = 299 K, there is solid CO₂, so initial volume is zero

We need to calculate the moles of CO₂

We know, mole = mass / molar mas

So, moles of CO₂ = 8.34 g / 44.0 g.mol^-1

                            = 0.189 moles

So we have given moles, volume and temp, so using the Ideal gas law we can calculate pressure.

We know,

PV = nRT

P = nRT / V

= 0.189 moles * 0.0821 L.atm.mol^-1.K^-1 * 299 K/ 1.00 L

= 4.65 atm   

So answer for this is C) 4.65 atm