Question

Aspirin is made by reacting salicylic acid with acetic anhydride in a 1:1:1 ratio. How many grams of aspirin are produce...


Aspirin is made by reacting salicylic acid with acetic anhydride in a 1:1:1 ratio. How many grams of aspirin are produced if 85.0 g of salicylic acid is reacted with excess acetic anhydride?

Answer

Aspirin is made by reacting salicylic acid with acetic anhydride in 1:1:1 ratio.

Acetic anhydride is present in excess.

Aspirin production is represented by the following reaction:

Chemical Engineering homework question answer, step 2, image 1

Chemical Engineering homework question answer, step 2, image 2

It is given 1 mole of salicylic acid reacts with 1 mole of acetic anhydride to produce 1 mole of aspirin.

The molecular weight of salicylic acid = 138.12 g/mol

The molecular weight of acetic anhydride = 102.9 g/mol

The molecular weight of aspirin = 180.16 g/mol

The weight of salicylic acid = 85 g

The number of moles of salicylic acid is calculated as follows:

Number of moles = given weight/molecular weight

Chemical Engineering homework question answer, step 3, image 1

Where n represents the number of moles

Plugin the values in equation (2)

Chemical Engineering homework question answer, step 3, image 2

The amount of aspirin required when 85 g of salicylic acid reacts with excess acetic anhydride is calculated as follows:

From the stoichiometry of the reaction, 1 mole of salicylic acid reacts with the 1 mole of acetic anhydride to produce 1 mole of aspirin.

For 1 mole of salicylic acid, aspirin produced 1 mole.

Therefore, for 0.615 moles of salicylic acid, aspirin produced 0.615 moles.

Number of moles of aspirin produced = 0.615 moles

The molecular weight of aspirin = 180.16 g/mol

Chemical Engineering homework question answer, step 4, image 1

Plugin the values in equation (3)

Chemical Engineering homework question answer, step 4, image 2

Therefore, the grams of aspirin produced = 110.79 g

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