The context of the problem is a boiling point elevation problem where two substa

Question

The context of the problem is a boiling point elevation problem where two substances are dissolved into pure liquid chloroform. I am able to do the first two steps of the problem and based on freezing point calculations, I arrived on the following intermediate step to the final step, where I am lost:<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

the two substances are: toluene with molar weight 92.14grams/ 1mole and mesitylene with molar weight 120.19grams/1mole

the combined moles (toluene and mesitylene) in solution: 0.0489 moles

Need to find the individual moles for each substance, i.e. moles toluene and moles mesitylene, that make the total of 0.0489 moles or that add up to 5.0237 grams.

If I set substance toluene = X and substance mesitylene = Y, I can set up the nect step the following:

1.) X + Y = 5.0237grams

2.) X + Y = 0.0480 moles where y = (0.0489 - X) moles

I know I need to substitute the y - expression in terms of X into the first equation and then solve for X. But somehow my math skills are lacking when I put in the numbers and I am stuck.

I need the solution to this for both the amount of moles of X and moles of Y. I know the molar weight (see above) of each substance needs to be used, I just can't do the last steps mathematically. So please help. I need the problem worked out with the steps and numbers included.

Explanation / Answer

see, we know that moles= given weight/molar mass

so let the mass of toluene= x

mass of mesitylene=5.0237-x

moles of toluene= x/92.14

moles of mesitylene=(5.0237-x)/120.19

Now this has reduced the no of variable to only x. hence putting in the equation find the value of x.

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