Asprin

Place on your blog the answers and steps (process) to this student's aspirin lab questions from Organic Chemistry I:
   "I started with 2.0 g of salicylic acid and 5 g of acetic anhydride and I got 2.1 g of acetylsalicylic acid (aspirin).  What is my theoretical yield and my percent yield?"

	C7H6O3        +     C4H6O3        ->    C9H8O4       +  HC2H3O2
Grams	2.0g	5.0g	2.612g
Molar mass	138.12	102.09	180.15
Moles	.0145	.0490	.0145
Limiting reagent	x

2.0g of C₇H₆O₃  x         1 moles   _ =  .0145 moles of  C₇H₆O₃

                               138.12g

5.0g of C₄H₆O₃  x         1 moles   _ =  .0490 moles of  C₄H₆O₃

                               102.09g

.0145 moles of C₉H₈O₄  x      180.15g   _ =  2.612g of C₉H₈O₄

                                         Moles

Theoretical yield of C₉H₈O₄ is 2.612g

Percent yield is 2.1g / 2.612g x100 = 80.4%



March 23

Limiting Reagents

Today in class we discussed limiting reagents.  On your blog, describe the process you used to determine how many quarter pound hamburgers could be made.

To determine how many quarter pound hamburgers I could make, I used a recipe (unit converter) and an order list (supplies) to begin.  From there, I found the limiting factor by multiplying the recipe and the order list together.  Some of the ingredients on the recipe required more than one of that ingredient (2 pieces of cheese) to create a quarter pounder.  From the list I created, I looked for the smallest number and concluded that the lowest number was the limiting factor.

For the following reaction, determine which reagent is limiting and how much of the product can be made:

Begin with 8.5 g of hydrogen (H₂) and 40.2 g of oxygen (O₂).

Post you answer and process for solving this question.

	2H2                       +                     O2                       →                   2H2O
Grams	8.5g	40.2g	22.61g
Molar Mass	2.016	32.0	18
Moles	4.216	1.256	1.256
LR	2.11	1.256 x

8.5g of H₂  x          1 mole   _  = 4.216 moles of H₂

       2.016g

40.2g of O₂  x         1 mole   _  = 1.256 moles of O₂

         32.0g

The limiting reactant is Oxygen

1.256 moles of H₂O  x        18g   _ = 22.61g of H₂O

                                     Moles

Daily Post 29/2/12

On your blog post practical examples of the types of reactions we are studying in class.  Perhaps these are reactions related to your career interest, or just of interest!

Acid-Base reaction

HCl + NaOH -> H₂O + NaCl

The combination of Hydrochloric acid and Sodium Hydroxide can be useful when stomach acid levels are higher than normal and need to be equalized.

PPT reaction

2Al(OH)₃ + 3H₂SO₄ -> Al₂(SO₄)₃ + 6H₂O

I find this reaction interesting because the Aluminum Hydroxide purifies the water molecules.

REDOX reaction

Fe +2 H₂O -> Fe(OH)₂ + 2H

In this reaction, the iron is being oxidized by the water molecules to form rust. I can relate this reaction to winter driving because when the snow sticks to the car causing oxidation to occur.

Gas forming reaction

CH₄ + H₂O -> CO_(g) + H_{2 (g)}

The combination between methane and steam is used to produce hydrogen gas and carbon monoxide. I find this reaction interesting because hydrogen in gaseous form can be used for multiple applications. 

Examples to include: PPT, REDOX, gas forming, and acid-base. Post the balanced reaction and why it is of interest to you.