Question

Using the concentration of the base and the volume of the base used, calculate the moles of the base used in the titration. Then, using the mass of the acid, determine the molar mass of the acid.

Data:
Concentration of the Base(NaOH)= 0.19 M
Volume of the Base used= 8.72 mL
Mass of the Acid(unknown)= 0.33 g

Answer 1

`\boxed{\text{(a) 0.001 66 mol MOH; (b) 200 g/mol}}`

Step-by-step explanation:

I am assuming that the unknown acid is monobasic. Then the general equation for the reaction is

HA + MOH ⟶ MA + H₂O

(a) Moles of MOH

`\text{Moles of MOH}= \text{0.008 72 L MOH} * \frac{\text{0.19 mol MOH}}{\text{1 L MOH}} = \text{0.001 66 mol MOH}`

(b) Moles of HA

Now, you use the molar ratio from the balanced chemical equation to find the moles of unknown acid.

`\text{Moles of HA = 0.001 66 mol MOH} * \frac {\text{1 mol HA}}{\text{1 mol MOH }} = \text{0.001 66 mol HA}`

(c) Molar mass of HA

`\text{MM} =\frac{\text{mass}}{\text{moles}}= \frac{\text{0.33 g}}{\text{0.001 66 mol}} = \text{200 g/mol}`

The molar mass of the unknown acid is
`\boxed{\textbf{200 g/mol}}`