At 20 degrees celsius the vapor pressure of dry ice is 56.5atm. If 10 g of dry ice (solid CO2) is placed in an evacuated 0.25 L chamber at a constant temperature of 20 degrees celsius, will all of the solid
sublime?
Is the answer no? I don't know if this is right, but I used the ideal gas law to see what the pressure would be in the chamber and got 21 atm. I compared that to the 56.5 atm, but I'm not sure what the answer is because it's lower.
To determine whether all of the solid dry ice will sublime in the given conditions, we need to compare the vapor pressure of dry ice at 20 degrees Celsius (56.5 atm) with the pressure in the chamber.
You correctly used the ideal gas law to calculate the pressure in the chamber. The ideal gas law equation is:
PV = nRT
Where:
P = Pressure
V = Volume
n = Number of moles
R = Ideal gas constant
T = Temperature
To find the number of moles (n), we need to convert the mass of dry ice into moles. The molar mass of CO2 is approximately 44.01 g/mol.
n = (mass of dry ice) / (molar mass of CO2)
n = 10 g / 44.01 g/mol
n ≈ 0.227 moles (rounded to three decimal places)
Now we can substitute the values into the ideal gas law equation:
P * V = n * R * T
P * 0.25 L = 0.227 mol * (0.0821 L·atm/(mol·K)) * (20 + 273.15) K
P * 0.25 L = 0.227 mol * 0.0821 L·atm/mol·K * 293.15 K
Simplifying the equation gives:
P = (0.227 * 0.0821 * 293.15) / 0.25
P ≈ 16.6 atm (rounded to two decimal places)
Now we compare the pressure in the chamber (16.6 atm) with the vapor pressure of dry ice (56.5 atm). Since the pressure in the chamber is lower than the vapor pressure of dry ice, not all of the solid dry ice will sublime. The remaining solid will maintain its frozen state in the chamber.
Therefore, your answer is correct.