1) Aspirin (C 9 H 8 O 4 ) is synthesized by mixing salicylic acid (C 7 H 6 O 3 )

Question

1) Aspirin (C9H8O4) is synthesized by mixing salicylic acid (C7H6O3) with excess acetic anhydride (C4H6O3). The balanced equation is:

C7H6O3 + C4H6O3 ------------> C9H8O4 + C2H4O2

Molar mass/ g.mol^-1

C2H4O2            60

C4H6O3            102

C7H6O3            138

C9H8O4             180

When 2.0g of salicylic acid is mixed with excess acetic anhydrude, 1.7g of aspirin is collected . What is the percent yield for this reaction?

2) Starting with 4.3 L if 0.58 M Na2CO3(aq) what volume of this solution is needed to prepare 250 mL of 0.20 M Na2CO3(aq) solution?

3) If 26.32 mL of .100 M H2SO4 is exactly neutralized by 34.56 of NaOH solution, what is the molar concentration?

4) A solution is prepared by dissolving 3.422g of Al2(SO4)3, molar mass 342.2 g.mol^-1, in water to obtain 0.100 L of solution. What is the molar concentration of sulfate ion in this solution?

Please explain! Step by step if possible! Thank you!

Explanation / Answer

1) by the given reaction

C7H6O3 + C4H6O3 ------------> C9H8O4 + C2H4O2

1 mole of salicylic acid should give 1 mole of aspirin

that is 138 g of salicylic acid should give 180 g of aspirin

let 2 g of salicylic acid give x g of aspirin

then x= 2 *180/138 = 2.61 g

so 2 g of salicylic acid should give 2.61 go aspirin

but give only 1.7 g aspirin is obtained

so percentage yield= 1.7/ 2.61 x100

percentage yield is 63.13 %

2) Final requirement is 250 mL of 0.20 M of Na2CO3 solution

moles = molarity x volume /1000

= 0.20 x 250/1000

moles=0.05

these moles should come from 0.58 M Na2C03

so conc=moles x 1000/volume

0.58= 0.05x1000/volume

volume= 86.02 ml

3)

2NaOH + H2SO4 -> Na2SO4 + 2H20

for H2SO4 Normality = molarity x 2

consider N1V1=N2V2

that is 0.2 x 26.32 = 34.56 x N2

N2= 0.15 N

for NaOH molarity = normality

Molarity = O.15 M

4) Given mass=3.422 g and M.w = 342.2 g and volume=0.1 L

conc= mass /M.W x Volume(L)

= 3.422 /342.2 x0.1

conc= 0.1 M

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.