When you get a chance:

If the pure liquid vapor pressure of benzene is 155 torr and the pure liquid vapor pressure of chloroform is 333 torr, then what is the total vapor pressure at 30°C of a solution of 9.26 g of benzene (C6H6) and 4.26 g of chloroform (CHCl3)?

I get 195torr.

I obtained 196 torr using 78.11 for molar mass C6H6 and 119.377 for molar mass CHCl3.

Okay, the answer choices were

The answer choices are:

375 torr
119 torr
195 torr
76.3 torr

When I performed the calculations, I also calculated 196, so i wasn't sure. I don't know if you remember ever taking a multiple choice that required using math as a kid and when you calculated a number, you chose the answer choice closest to the number that matched the number you calculated and getting the answer wrong because of that; I wasn't sure I reverted to a habit that I did as a child, so I wanted a check.

Okay, the answer choices are:

375 torr
119 torr
195 torr
76.3 torr

When I performed the calculations, I also calculated 196 torr after rounding up, so I wasn't sure. I don't know if you remember ever taking a multiple choice exam that required using math as a kid and when you calculated a number, you chose the answer choice closest to the number that matched the number you calculated and having the answer marked wrong because of that; I wasn't sure if I reverted to a habit that I did as a child, so I wanted someone to check it.

I remember taking a multiple guess test in which I picked the closest number to what I calculated but I don't remember it being wrong. I would pick 195 torr also since "none of the above" is not a choice.

You were more careful then I was as I child. Sometimes I would get careless, or I would just move to fast and not check my work; I do that a lot with my typing. I didn't start applying myself in school until my second year in college. Once I start applying myself, I started to set the curve in some of my courses, or I was at the least one of the sharks and the class. I also began to figure out that I was a nerd.

I didn't want to tell someone something wrong when I was asked about this problem, and if I was wrong, you would tell me.

Thank you

To find the total vapor pressure at 30°C of the solution containing benzene and chloroform, you need to apply Raoult's law. According to Raoult's law, the partial pressure exerted by each component of an ideal solution is directly proportional to its mole fraction in the solution.

First, you need to calculate the mole fraction of benzene (C6H6) and chloroform (CHCl3) in the solution. To do this, you can use the following formula:

Mole Fraction (benzene) = Moles of benzene / Total moles of both components
Mole Fraction (chloroform) = Moles of chloroform / Total moles of both components

Next, calculate the partial vapor pressures of benzene and chloroform using their respective mole fractions and pure liquid vapor pressures:

Partial Pressure (benzene) = Mole Fraction (benzene) * Pure liquid vapor pressure (benzene)
Partial Pressure (chloroform) = Mole Fraction (chloroform) * Pure liquid vapor pressure (chloroform)

Finally, find the total vapor pressure by summing up the partial pressures of both components:

Total Vapor Pressure = Partial Pressure (benzene) + Partial Pressure (chloroform)

Let's calculate it step by step:

Step 1: Calculate the moles of benzene (C6H6) and chloroform (CHCl3)
Moles (benzene) = Mass (benzene) / Molar mass (benzene)
Molar mass (benzene) = 78.11 g/mol
Moles (benzene) = 9.26 g / 78.11 g/mol

Moles (chloroform) = Mass (chloroform) / Molar mass (chloroform)
Molar mass (chloroform) = 119.38 g/mol
Moles (chloroform) = 4.26 g / 119.38 g/mol

Step 2: Calculate the mole fraction of benzene and chloroform
Total moles of both components = Moles (benzene) + Moles (chloroform)

Mole Fraction (benzene) = Moles (benzene) / Total moles of both components
Mole Fraction (chloroform) = Moles (chloroform) / Total moles of both components

Step 3: Calculate the partial vapor pressures of benzene and chloroform
Partial Pressure (benzene) = Mole Fraction (benzene) * Pure liquid vapor pressure (benzene) = Mole Fraction (benzene) * 155 torr
Partial Pressure (chloroform) = Mole Fraction (chloroform) * Pure liquid vapor pressure (chloroform) = Mole Fraction (chloroform) * 333 torr

Step 4: Calculate the total vapor pressure
Total Vapor Pressure = Partial Pressure (benzene) + Partial Pressure (chloroform)

Now, plug in the values and calculate the total vapor pressure:

Mole Fraction (benzene) = (9.26 g / 78.11 g/mol) / (9.26 g / 78.11 g/mol + 4.26 g / 119.38 g/mol)
Mole Fraction (chloroform) = (4.26 g / 119.38 g/mol) / (9.26 g / 78.11 g/mol + 4.26 g / 119.38 g/mol)

Partial Pressure (benzene) = Mole Fraction (benzene) * 155 torr
Partial Pressure (chloroform) = Mole Fraction (chloroform) * 333 torr

Total Vapor Pressure = Partial Pressure (benzene) + Partial Pressure (chloroform)