Question

Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation is given below.
C7H6O3 + C4H6O3 C9H8O4 + HC2H3O2

What mass of acetic anhydride is needed to completely consume 3.60 x 10^2 g salicylic acid?

i worked out the problem and got 270 but the answer is 370. here is my work.


360g C7H6O3 x 1 mol C7H6O3/138.118 g C7H6O3 x 1 mol C4H6O3/ 1 mol C7H6O3 x 102.088 g C4H6O3/1 mol C4H6O3 = 270g C4H6O3


sorry that looks really confusing but is there something wrong with my conversion factor??

Answer 1

Your work would not look so confusing if you used parentheses. For example,
360 g C6H7O3 x (1 mol C6H7O3/138.118) x .....
Your work looks ok, however, I ran this on my calculator and obtained 266.08 grams. (I also used 138.123 instead of 138.118 but I don't think that will make any significant difference). Are you keying this into a database? If so, and 266 doesn't work, I would try 2.66 x 10^2 since the problem was given in scientific notation.

Answer 2

I agree with you, mol masses 138 and 102
C7H6O3 + C4H6O3 ---> C9H8O4 + HC2H3O2
360/138 or 2.61 mole of C7H6O3
and therefore
2.61 mol of C4H6O3
2.61 = x/102
x = 267
(I did not carry all the decimal places)

Answer 3

I agree with you, mol masses 138 and 102
C7H6O3 + C4H6O3 ---> C9H8O4 + HC2H3O2
360/138 or 2.61 mole of C7H6O3
and therefore
2.61 mol of C4H6O3
2.61 = x/102
x = 267
(I did not carry all the decimal places)

Answer 4

Your work would not look so confusing if you used parentheses. For example,
360 g C6H7O3 x (1 mol C6H7O3/138.118) x .....
Your work looks ok, however, I ran this on my calculator and obtained 266.08 grams. (I also used 138.123 instead of 138.118 but I don't think that will make any significant difference). Are you keying this into a database? If so, and 266 doesn't work, I would try 2.66 x 10^2 since the problem was given in scientific notation.

Answer 5

360g C7H6O3 x 1 mol C7H6O3/138.118 g C7H6O3 x 1 mol C4H6O3/ 1 mol C7H6O3 x 102.088 g C4H6O3/1 mol C4H6O3 = 270g C4H6O3