We are asked to calculate the total pressure after the stopcocks were opened.
Opening the stopcock will essentially change the volume for each component.
We go through the following steps to solve the problem:
Step 1. Calculate the pressure of N2 after the volume change
Step 2. Calculate the pressure of H2O if all of it evaporated and compare to the vapor pressure.
Step 3. Calculate the pressure of ethanol if all of it evaporated and compare to the vapor pressure.
Step 4. Calculate the total pressure.
Step 1.Calculate the pressure of N2 using Boyle's Law:
P1 = 1.1 atm
V1 = 1.0 L (1 flask)
V2 = 3.0 L (3 flasks)
Also, convert to atm to torr
1 atm = 760 torr
P2 = 279 torr
PN2 = 279 torr
Three 1.0 L flasks maintained at 310K are connected to each other with stopcocks, initially closed. One flask contains 1.10 atm of N2; the second 2.25 g H2O(l); and the third, 0.450 g of ethanol(l), FW 46.1 g/mol. The vapor pressure of water at 310K is 43 torr and that of ethanol is 104 torr. When the stopcocks are opened and the contents mix freely, what is the final total pressure in torr?
A. 385 torr
B. 1705 torr
C. 836 torr
D. 806 torr
E. 551 torr
Frequently Asked Questions
What scientific concept do you need to know in order to solve this problem?
Our tutors have indicated that to solve this problem you will need to apply the The Colligative Properties concept. You can view video lessons to learn The Colligative Properties. Or if you need more The Colligative Properties practice, you can also practice The Colligative Properties practice problems.
What professor is this problem relevant for?
Based on our data, we think this problem is relevant for Professor Heinrich's class at UA.