Question

In a 250mL Erlenmeyer flask, a 0.50 gram piece of dry ice is allowed to completely sublime and the pressure goes from 0.95 to 2.06 atm at a temperature of 24 degrees Celsius. Calculate the Gas Law Constant. I got ~0.693 as the constant.

I changed 250ml to L = 0.25 L
24 C = 297.15 K
I wasn't sure if I was right about the pressure, so I subtracted 0.95 from 2.06.
I used PV/nt = r

Thank you!

Answer 1

Initial pressure = 0.95 atm

Final pressure = 2.06 atm

pressure due to CO₂ = 1.11 atm

Volume of CO₂ = 0.25 L

mass of CO₂ = 0.50 g

moles of CO₂ = mass of CO₂ / molar mass of CO₂

moles of CO₂ = (0.50 g) / (44.0 g/mol)

moles of CO₂ = 0.011364 mol

Temperature = 297.15 K

R = (P * V) / (n * T)

R = (1.11 atm * 0.25 L) / (.011364 mol * 297.15 K)

R = 0.08218 L-atm/mol-K

Actual value of R is 0.082057 L-atm/mol-K

Hence the value obtained from calculations is very close to actual value