High School

We appreciate your visit to 1 A mass of 9 73 g of an unknown water soluble monoprotic weak acid is present in 125 mL of solution After 50 0. This page offers clear insights and highlights the essential aspects of the topic. Our goal is to provide a helpful and engaging learning experience. Explore the content and find the answers you need!

1. A mass of 9.73 g of an unknown, water-soluble, monoprotic weak acid is present in 125 mL of solution. After 50.0 mL of 1.00 M NaOH is added, the equivalence point is reached. What is the molecular weight of the unknown?

A. 55.6 g/mol
B. 64.9 g/mol
C. 97.3 g/mol
D. 195 g/mol
E. 389 g/mol

Answer :

The molecular weight of the unknown weak acid is approximately 2.5 g/mol.

To determine the molecular weight of the unknown weak acid, we can use the concept of acid-base titration and the equation:

M1V1 = M2V2

Where:

M1 = Initial concentration of the acid (unknown)

V1 = Initial volume of the acid solution

M2 = Final concentration of the acid (after reaching the equivalence point)

V2 = Final volume of the acid solution

Given:

Mass of the unknown acid = 9.73 g

Volume of the acid solution = 125 mL

Volume of NaOH added = 50.0 mL

Concentration of NaOH = 1.00 M

First, we need to calculate the initial concentration of the unknown acid:

M1 = (mass of the unknown acid) / (volume of the acid solution)

= 9.73 g / 0.125 L (since 125 mL = 0.125 L)

= 77.84 M

Next, we can calculate the final concentration of the acid after reaching the equivalence point. At the equivalence point, the moles of NaOH added are equal to the moles of the weak acid initially present. Therefore, we can use the equation:

M1V1 = M2V2

(77.84 M) × (0.050 L) = M2 × (0.100 L) (since 50 mL = 0.050 L)

Solving for M2:

M2 = (77.84 M × 0.050 L) / 0.100 L

= 38.92 M

Finally, to find the molecular weight (molar mass) of the unknown weak acid, we can use the formula:

Molar mass = (mass of the unknown acid) / (moles of the unknown acid)

Moles of the unknown acid = (final concentration of the acid) * (final volume of the acid solution)

= 38.92 M × 0.100 L

= 3.892 moles

Molar mass = 9.73 g / 3.892 moles

= 2.5 g/mol

Therefore, the molecular weight of the unknown weak acid is approximately 2.5 g/mol.

To know more about Molar mass:

https://brainly.com/question/31307837

#SPJ4

Thanks for taking the time to read 1 A mass of 9 73 g of an unknown water soluble monoprotic weak acid is present in 125 mL of solution After 50 0. We hope the insights shared have been valuable and enhanced your understanding of the topic. Don�t hesitate to browse our website for more informative and engaging content!

Rewritten by : Barada