# Chemistry

Does anyone know how to do this problem, i can't seem to solve it.

If 39.25 g of a substance is dissolved in 155.5 g of benzene solvent, the freezing point of the solution is 0.08 oC. Calculate the apparent molar mass (g/mol) of substance.

asked by SuSu
1. delta T = Kf*molality.
molality = moles solute/kg solvent.
moles = g/molar mass.
Post your work if you gst stuck.
Use equation 1 to solve for molality.
Use equation 2 to solve for moles solute.
Use equation 3 to solve for molar mass.

posted by DrBob222
2. so this is what i did,

0.08C = (5.065Ckg/mol)(x/0.1555) which is 0.002456071.

i then took 39.25g/0.002456071 which is 15980 g/mol.

This seems to big for molar mass of a substance

posted by SuSu
3. Mistake 1. delta T is not 0.08. The problem states that the freezing point of benzene is 0.08 C. You must have or must look up the normal freezing point of benzene and subtract 0.08 to arrive at delta T.
#2. I found 5.12 for the Kf for benzene and the units are oC/m. I don't understand the units you have but the number you have used is not that much different than what I used..

I ran through the problem VERY roughly and obtained something in the neighborhood of 240 for the molar mass.

posted by DrBob222

## Similar Questions

1. ### English

1. He can not solve the math problem. 2. He cannot solve the math problem. 3. He can't solve the math problem. 4. He could not solve the math problem. 5. He couldnot solve the math problem. 6. He couldn't solve the math problem.
2. ### Pre calculus

How do I solve this exponent problem? I understand the exponent rules, but I getting 1 but 1 is not the answer! I don't want anyone to solve the problem for me, I want to learn how to solve this type of problem. Thank you! Solve
3. ### MATH

in a contest, Bello. Adamu, and Lawi are asked to solve a mathematical problem. the probability that they solve the problem correctly are 1/5, 2/3, and 2/5. find the probability that:(1)None of them solve the problem
4. ### Child development

Using these steps, consider a cognitive “problem” a young child might encounter that he/she needs help with (such as putting together a puzzle, sequencing – putting items in order, sorting by color or size, adding,
5. ### Problem solving:for 3rd grade

Write a real-world problem that you can solve by adding or subtracting.Then give your problem to a classmate to solve.
6. ### Need all the help i can get

Hi i'm pretty new to this and i don't know what to do?So i put these questions up im not sure if my answers will show up because i used color letters, but i need help checking and explaining steps N 108 is 36% of what number?
7. ### Math And Science for Young Children

The conventional problem-solving strategies usually taught have been: A. act out the problem, make a drawing or diagram, and solve the problem. B. look for a pattern, construct a table, solve the problem, and look back. C.
8. ### statistics

34. Two students (say A, and B) are challenged to solve a problem in statistics. Suppose that the probability that A will solve the problem is 40%, the probability that B will solve the problem is 55%, and the probability that A
9. ### math

i don't get how to do this problem mrs. sue please help how would you convert the repating nonterminating decimal to a fraction? explain the process as you solve the problem/0.1515... remember to show all of the steps that you use
10. ### English

1. The problem is so difficult that I cannot solve it. 2. The problem is too difficult for me to solve. 3. It is too difficult for me to solve the problem. (Are the three sentences the same? Do they come from the same structure?
11. ### geometric

I need help on this following problem: The length of a rectangle measures 1 cm less than its width. The perimeter of the rectangle is 106 cm. Find the dimensions of the rectangle. Now i have tried to solve this problem in multiple

More Similar Questions