Question

Salicylic acid (C7H6O3) reacts with acetic anhydride (C4H6O3) to form acetylsalicylic acid (C9H8O4). 2C7H6O3(aq) + C4H6O3(aq) mc002-1.jpg 2C9H8O4(aq) + H2O(l) What is the limiting reactant if 70.0 g of C7H6O3 and 80.0 g of C4H6O3 react?

Answer 1

Answer: B) Salicylic acid

Explanation: i just took the test !!!!!

Answer 2

In order to understand what is the limiting reactant is useful to convert the masses of reactants into moles. The molecular masses are:


`C_7H_6O_3 = 138(g)/(mol)\\ C_4H_6O_3 = 100(g)/(mol)`

Converting masses into moles:


`70\g \C_7H_6O_3\cdot (1\ mol)/(138\ g) = 0.5\ mol\ C_7H_6O_3`


`80\ g\ C_4H_6O_3\cdot (1\ mol)/(100\ g) = 0.8\ mol\ C_4H_6O_3`

In the reaction, 2 moles of
`C_7H_6O_3` are necessary to react with 1 mol of
`C_4H_6O_3`. Following this ratio:


`0.8\ mol\ C_4H_6O_3\cdot (2\ mol\ C_7H_6O_3)/(1\ mol\ C_4H_6O_3) = 1.6\ mol\ C_7H_6O_3`

We have only 0.5 mol of
`C_7H_6O_3`, i.e, we don't have enough amount of salicylic acid, therefore, this is the limiting reactant.