Graded on Percent Yield in Organic Lab???

[ChymeofPassion]

Just wanna get a feel for how many people are/aren't, because I've heard both depending on the school.

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[doctorleospaceman]

Welcome to organic chem lab.

It's all about percent yield and then the write up. I mean, what else is there to grade you on except your patience towards watching water boil before you go get lunch or do something else?

 

[IJumpYouJumpJack]

My organic lab wasn't graded on percent yield, and was just graded on our post-lab write up. But we were also not given extra credits for lab, even though based on the amount of time we spent in lab it should have been an extra 1 or 2 credits.

 

[enchantediris]

We were technically graded on yield, but I think as long as you made a good faith effort and didn't end up with a ridiculously small yield, you were fine. They cared more about your structures, reactions, and calculations in the lab report.

 

[ChymeofPassion]

For people that were graded on percent yield, was there a scale? 70-100 percent yield=A, 60-70=A-, etc?

 

[Brawndo2016]

Thank goodness we were not graded on percent yield, but on how we explained our results. My grade would have been considerably lower if I had to produce anything close to the desired yield. Not a chemist, glad it's over and never want to return.

 

[Lawpy]

 

[doctorleospaceman]

For people that were graded on percent yield, was there a scale? 70-100 percent yield=A, 60-70=A-, etc?

Depended on how the rest of our lab did. Best group set the bench mark then if you were within some percent you got full points rest you got less.

And for one I find this totally fair. The lecture portion is all comprehension. The lab is about how well you actually do and understand the lab. If you just rush through it but understand the basic elementary mechanism then the 3 hour lab is moot.

 

[You're My Boy Blue]

We were graded on purity typically based on melting point, not percent yield. I've never understood grading on %yield..essentially your reaction can be complete garbage but hey as long as there's enough of it good job? Besides I could see people adding in more reactant to increase the
"yield"

Edit: Also IR Spectroscopy

 

[doctorleospaceman]

We were graded on purity typically based on melting point, not percent yield. I've never understood grading on %yield..essentially your reaction can be complete garbage but hey as long as there's enough of it good job? Besides I could see people adding in more reactant to increase the
"yield"

Well it's percent yield of product with a reasonable melting point/spectroscopy.

 

[citykid92]

Mine was graded partially on percent yield. It tended to be a small percentage of the grade though.

 

[Lifeblood_20]

Mine was graded partially on percent yield. It tended to be a small percentage of the grade though.

If my percent yields are my grades I wouldn't have passed the class... Lol

 

[citykid92]

Yeah me neither lol. Purity was always way more important than yield for us.

 

[Eagleye2]

hey guys, yeah both my orgo labs were graded on percent yield AND purity by melting point. Grades are set by looking at how the best of the bunch did and then scaling down from there. In all honesty, it has been pretty kind to me. Sometimes ill get a 40% yield and have it be a 23/25. Other times.... 0% yield 🙁. gotta love orgo lab

 

[DameJulie]

Two out of three quarters of Ochem was I graded on percent yield

 

[kb1900]

Wouldn't most samples still be 'wet' and not give accurate % yields until you wait about a few hours for them to dry? I remrmber that most labs my % yield was >100% unless I recorded the mass the following week.

Anyway we were graded on:
1) post lab write up
2) technique during lab
3) purity by TLC vs standards
4) mp

 

[Lucca]

Good yields for experiments can vary. If an undergrad gets 100% yield on a Grignard reaction for example on an extremely humid day then they are either lying or the second coming of Emile Fischer. Our prof would usually say "most students get between 70-80% yield for this" some days and less on others. In any case, it was not part of our grade to get some amount of yield.

 

[kb1900]

Good yields for experiments can vary. If an undergrad gets 100% yield on a Grignard reaction for example on an extremely humid day then they are either lying or the second coming of Emile Fischer. Our prof would usually say "most students get between 70-80% yield for this" some days and less on others. In any case, it was not part of our grade to get some amount of yield.

Ha

The second Synthesis lab we did, by dumb luck, I got 98% yield with no identifiable impurities in NMR or TLC. The running joke the entire semester was that I should become a home chemist aka drug producer a la breaking bad

 

[Lucca]

Ha

The second Synthesis lab we did, by dumb luck, I got 98% yield with no identifiable impurities in NMR or TLC. The running joke the entire semester was that I should become a home chemist aka drug producer a la breaking bad

You probably should. I'm a physical chemist and I find the voodoo mixology of Organic Chemistry to be tedious. Organic chemists are just people who wanted to be real chemists but were too afraid of math. /comeatme

 

[kb1900]

You probably should. I'm a physical chemist and I find the voodoo mixology of Organic Chemistry to be tedious. Organic chemists are just people who wanted to be real chemists but were too afraid of meth. /comeatme

Ftfy!

But yeah haha my friends getting his graduate degree now in organic chem. He's a math wiz and keeps saying he entered the wrong field with how much math he has to do for his entire lab....his PI can't even do a partial derivative without help!

 

[DocMcMommy]

If our percent yield was low, we were expected to discuss why and what should have happened instead in the lab report or worksheets. If you did that, then points were usually not taken away.


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[WedgeDawg]

Organic chem was several years ago for me, but I think I recall that ~3-5% of our grade for each lab was based on percent yield.

 

[BeddingfieldMD]

That was a while ago, but my recollection is that we had to meet a minimum amount of acceptable yield (with reasonable purity) and then were largely graded on our techniques and write-up. If we didn't meet a minimum yield or had a product that didn't seem to be what we were trying to produce, then we had to repeat the experiment. Of course, there were also a couple of lab exams throughout the semester that contributed to the grade. But it definitely wasn't a 70-79%=C, 80-89%=B kind of deal. That sounds brutal!

 

[Tutor526]

My lab was graded purely on pre-lab assignments and post-lab papers, I am feeling very thankful right now that percent yield or purity weren't included!

 

[altblue]

Does it have to be blue?

 

[Orthopedics101]

Wow....my orgo lab midterm (30% of my final grade) was graded on percent yield and purity.

 

[oznefu]

For me it was post lab write ups throughout the semester and one experimental yield on my final.


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[sullen-burger]

I think one or two of our assignments throughout both semesters were based on yield, and even then that wasn't the majority of the grade.

I think it definitely depends on the school, but I'd risk saying it depends more on the professor you get. For example, ours had taught long enough to never need lecture notes, so that was a + for some and a - for those who lived off of powerpoints. I personally think we had a ballin lab professor because we never had to do the "tedious" work other orgo classes did like memorizing specific reactions, just the types and classes for pattern recognition. Again, +/- to that.

You probably should. I'm a physical chemist and I find the voodoo mixology of Organic Chemistry to be tedious. Organic chemists are just people who wanted to be real chemists but were too afraid of math. /comeatme

I am so. So sorry.

 

[freak7]

We were graded on percent yield. Basically it led to 3/4 of the class lying about how much substrate they started with so that way they'd get super high % yield. I do not miss undergrad

 

[kb1900]

We were graded on percent yield. Basically it led to 3/4 of the class lying about how much substrate they started with so that way they'd get super high % yield. I do not miss undergrad

lol what?? U just pick how much reactant you start with??

At the beginning of every lab, TAs would watch students dispense their reagent on the scales and write down the starting amount to the thousandths place. Guess they learned ha

 

[Eagleye2]

lol what?? U just pick how much reactant you start with??

At the beginning of every lab, TAs would watch students dispense their reagent on the scales and write down the starting amount to the thousandths place. Guess they learned ha

Ours were already preweighed in vials... Lol no way to cheat the system

 

[AnatomyGrey12]

Ours was just the post-lab write ups and two exams. Getting good grades in the lab wasn't hard, but the tests were brutal to balance the grades out