Question

QUESTION 3

1. Salicylic acid reacts with acetic anhydride to form aspirin and acetic acid as shown. Use the equation to answer Questions 3 – 6.

         (salicylic acid)                                               (aspirin)               

   C7H6O3 (s) + C4H6O3 (l) → C9H8O4 (s) + CH3COOH (l)

     MM = 138 MM = 180

     If we divide 180 by 138 we find that 1.00 g salicylic acid will produce a maximum of 1.30 g aspirin.

   3. A student starts with 3.20 g salicylic acid. What is the maximum amount of aspirin she can make?

   	a.	4.16 g
   	b.	2.46 g
   	c.	3.20 g
   	d.	3.90 g
   	e.	None of the above

QUESTION 4

1. In another experiment she has produced 2.77 g of wet aspirin from 3.0 g salicylic acid. After crystallization she has 2.54 g of dry product. What is her percent yield for the experiment?

   	a.	85%
   	b.	71%
   	c.	77%
   	d.	65%
   	e.	None of the above

QUESTION 5

1. What would happen if 15 or 20 mL of water spilled into the Erlenmeyer flask before the reaction got started?

   	a.	Some or all of the acetic anhydride would get converted to acetic acid
   	b.	Some of the aspirin that forms would get converted back to salicylic acid
   	c.	The reaction would be unaffected
   	d.	The yield of aspirin would be reduced
   	e.	(a), (b), and (d) are true

QUESTION 6

1. Aspirin has more carbon, hydrogen, and oxygen atoms than salicylic acid. Compare the two formulas and count the number of each type of atom that aspirin has more of. Then choose the formula below that best represents the difference.

   	a.	C2H2O2
   	b.	C2H3O
   	c.	C2H2O
   	d.	C2H3O2
   	e.	None of the above

Question 7

18 M H₂SO₄ is used in the synthesis of aspirin. It has little or no water in it compared to lesser concentrations of sulfuric acid. What would happen if a person used 6 M instead of 18 M sulfuric acid in the procedure?

	a.	The yield of aspirin would be decreased
	b.	The yield of aspirin would be increased
	c.	The yield of aspirin would be unaffected because sulfuric acid is still present
	d.	The yield of aspirin would be unaffected because water also supplies H+
	e.	None of the above

QUESTION 8

1. When testing the final product with iron (III) chloride, what would a purple color indicate?

   	a.	Most of the final product is aspirin
   	b.	Most of the final product is salicylic acid
   	c.	Most of the final product is reacting with the iron (III) chloride
   	d.	Sulfuric acid turns the iron (III) chloride a purple color
   	e.	(a) and (d) are false

Answer 1

3. A

For every 1g of salicylic acid 1.3 g of aspirin is produced.

So for 3.2g of salicylic acid 3.2 × 1.3 = 4.16 g of aspirin is produced.

4. A

For 3g of salicylic acid 2.77 g of wet aspirin is produced and after removing water of crystallization 2.54 g of wet aspirin is present .

So the percent yield is (2.54g/3g ) ×100

= 84.66%

=85%

5. E

The aspirin product is not very soluble in water so the aspirin product will precipitate when water is added. So it will decrese the amount of aspirin produced.

water plus actetic anhydride equals acetic acid plus heat.

6. C

Salicylic acid = C7H6O3

ASPIRIN = C9H8O4

so the difference is C2H2O

7. A

6 M H2SO4 means less H2SO4 and more water while 18 M H2SO4 means more H2SO4 and less water.

More water will lead to more conversion of acetic anhydride to acetic acid this will lead to less production of aspirin .