Question

Hi, this is my first lab in 2nd semester of chemistry, and im not sure about my answers in the assignment can someone give it a quick look to check them?

this is my phase diagram:
tinypic. com/view.php?pic=1605yev&s=7

p.s. ignore the lone red dot its supposed to be 38C..

there were the questions:

Mass of lauric acid (from balance): 1.00 g

melting point of lauric acid (from excell): 42.5C

mass of benzoic acid (from balance): 0.246g

melting point of lauric acid/benzoic acid mixture: 34.0C

^Tf= (3.9 C/m)(0.246g/mol) / 0.001 = 959.4

Molecular mass of benzoic acid from calculations: 0.9594/0.0085=112.9

molecular mass of benzoic acid: (given by teacher) 122.2g/mol

%error= 959.4-122.12 / 122.12 X 100 = 690%

Im not sure about the percent error if i used the right numbers. can someone please help? i want to get a good grade on this assignment and its due Wednesday...

If i could just know if the percent error is correct that would be great, that's the one im most unsure of..

Answer 1

I looked only at the percent error. That should be[(112-122)/122] *100 = much better than 690%

Answer 2

lol, i thought the percent error was too high!