chem
posted by greeny .
Aspirin, C9H8O4, is produced from salicylic acid, C7H6O3, and acetic anhydride, C4H6O3:
C7H6O3 + C4H6O3 > C9H8O4 + HC2H3O2
a. How much salicylic acid is required to produce 1.5 x 10^2 kg of aspirin, assuming that all of the salicylic acid is converted to aspirin?
b. how much salicylic acid would be required if only 80 percent of the salicylic acid is converted to aspirin?
c. What is the theoretical yield of aspirin if 185kg of salicylic acid is allowed to react with 125kg of acetic anhydride?
d. If the situation described in part c produces 182kg of aspirin, what is the percentage yield?
I'm really confused on this problem, please help? thanks!

Figure out how much each compound weighs. Each side of the equation must have the same weight. So if you have 1.5x10^2 kg of aspirin, how much salicylic acid and acetic anhydride must you have to make that much PLUS have the required amount of HC2H3O2? For part B, multiple the weight of salicylic acid by 80% (0.80) and do the same calculations. For part C you must work "backwards" from the weights to determine what percent of aspirin is produced. Part D is the same as C but your yield drops by 3kg (so the percent should be lower by that much.

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