Two Flasks containing the same inert gas are at the same temperature and pressure of 800 mmHg. One flask has volume of 1.0 L and the other, a volume of 2.0 L. Enough volatile liquid is injected into each of the flasks to allow phase equilibrium to be established. No leakage occurs. If the pressure in the 1.0 L flask is 900 mm Hg, what is the pressure in the 2.0 L flask?
Jason--
When Bob Pursley answered your question this morning (it is much clearer now when you reposted--thanks) he told you the pressure would be the same. That means that the pressure in the 2L flask will be 900 mm Hg.
You can use PV=nRT for the 1L flask and calculate the mols of inert gas (assume any T but keep it constant) at 800 mm Hg pressure. Then do the same for 900 mm Hg pressure. Subtract the two to determine the number of mols of the new gas from the volatile liquid. Then calculate n for the mols of inert gas in the 2L flask, add twice the mols of volatile liquid gaseous molecules, and calculate the pressure. It will be 900 mm Hg. I hope this helps.
To find the pressure in the 2.0 L flask, you can follow these steps:
Step 1: Calculate the number of moles of inert gas in the 1.0 L flask at 800 mm Hg. Use the formula PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant (0.0821 L·atm/mol·K), and T is the temperature. Rearrange the equation to solve for n:
n = PV / RT
Since the temperature and gas are the same in both flasks, the number of moles of inert gas in the 1.0 L flask at 800 mm Hg is the same as in the 2.0 L flask.
Step 2: Calculate the number of moles of inert gas in the 1.0 L flask at 900 mm Hg. Use the same equation as in Step 1, but with the new pressure.
Step 3: Calculate the number of moles of volatile liquid gaseous molecules that were injected into the flasks. This can be done by subtracting the number of moles of inert gas at 800 mm Hg from the number of moles of inert gas at 900 mm Hg. This represents the extra moles contributed by the volatile liquid.
Step 4: Calculate the number of moles of inert gas in the 2.0 L flask. Since the number of moles of inert gas in the 1.0 L flask is the same as in the 2.0 L flask, you can use the result from Step 1.
Step 5: Add twice the number of moles of volatile liquid gaseous molecules (from Step 3) to the number of moles of inert gas in the 2.0 L flask (from Step 4). This gives you the total number of moles of gas in the 2.0 L flask.
Step 6: Calculate the pressure in the 2.0 L flask using the formula PV = nRT, similar to Step 1. Use the total number of moles of gas from Step 5 and the volume of the 2.0 L flask.
The result will be the pressure in the 2.0 L flask, which should be 900 mm Hg in this case.