Chemistry Practice Problems Equivalence Point Practice Problems Solution: A 0.167-g sample of an unknown acid requires 27.8 ...

Solution: A 0.167-g sample of an unknown acid requires 27.8 mL of 0.100 M NaOH to titrate to the equivalence point. Elemental analysis of the acid gives the following percentages by mass: 40.00% C; 6.71% H; 53.29% O.Determine the molar mass of the unknown acid.

Problem

A 0.167-g sample of an unknown acid requires 27.8 mL of 0.100 M NaOH to titrate to the equivalence point. Elemental analysis of the acid gives the following percentages by mass: 40.00% C; 6.71% H; 53.29% O.

Determine the molar mass of the unknown acid.

Solution

We have to determine the molar mass of the unknown acid using the given data.


When acid and a base react, the number of moles of the acid can be determined by the number of moles of the base using a balanced chemical equation.


We will solve this problem through these steps:

Step 1: Write a balanced equation for the acid-base reaction.

Step 2: Calculate the number of moles of NaOH from its volume and molarity.

Step 3: Calculate the number of moles of unknown acid.

Step 4: Calculate the molar mass of unknown acid.

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