Last Section of Stoich_ Percent of Yields

October 22nd 2012

Hello guys basically what we did today- those of you who were absent today- is we took stoich quiz #5 and learned last step of STOICH. Since we were working with Stoichiometry 2 weeks from now, we know how to convert gram to mole, mole to gram, gram to gram, and finally PERCENT OF YIELDS!!!!! :) 


As you see above, percent of yield is really really really simple and easy. 

• Percent of Yield is a comparison of the amount actually obtained to the amount it was possible to make. 

• Actual yield is the amount of product actually obtained from a chemical reaction.(Must be experimentally determined, cannot be calculated) Usually the problem or lab date gives the actual yields. 

• Theoretical yield is the maximum amount of product that can be get in a chemical reaction. You must calculate with stoich step to get theoretical yields. 

Hmm. Lets solve one problem together. 

Boom. You have given formula and question. 
This question is asking us to solve theoretical formula and find percent of yield. 
First, you need back up your memory to determine which one is limiting reactant. 
Lets find the limiting reactant :

1. Assume  
   C₂H₅OH is the limiting reactant and calculate how much C₂H₅Cl would be formed.
2. Also assume that  PCl₃ is the limiting reactant too. 

Oh, sorry for huge equations.

• The reactant producing the smaller amount of C₂H₅Cl is the limiting reactant which is PCL3 
• Corresponding quantity of C₂H₅Cl  is the theoretical yield

Limiting reactant= PCl3 

Theoretical yield= 48.9g 

Now calculating percent of yield is piece of cake, which is : (Sorry, huge pic!)

We found Percent of Yield!!!

Homework:

Finish percent of yield worksheet

Ready for Wednesday's EXAM

Our Next scribe is (Plz make a drum sound) Eddy Rohhhhhhhh! Good luck ;) 

Have an awesome midnight homework time guys.. I have to do my rest of the homework ehh. ;(