Question

A student prepared a 1:1 buffer, for which [HAc] = [Ac-] = 0.04858 M. Using their 1:1 buffer and a 0.09916 M HCl solution, the student prepared Solution C in Part 3 of the experimental procedure. Given this information, how many moles of Ac- were there in the student's Solution C before a reaction took place? Report your final answer, in moles, to 6 decimal places and only include the numerical value (no units). Do not use scientific notation to answer this question.

Answer 1

To find the moles of Ac- in Solution C before a reaction took place, we need to calculate the volume of the 0.09916 M HCl solution used and then use the concentration of Ac- in the buffer and the volume of HCl solution to calculate the moles of Ac-.

Step-by-step explanation:

The student prepared a 1:1 buffer with [HAc] = [Ac-] = 0.04858 M. To find the moles of Ac- in Solution C before a reaction took place, we first need to determine the volume of the 0.09916 M HCl solution used. Then we can use the concentration of Ac- in the buffer and the volume of HCl solution to calculate the moles of Ac-.

Step 1: Calculate the volume of HCl solution used. Using the formula M1V1 = M2V2, where M1 and V1 are the concentration and volume of the HCl solution, and M2 and V2 are the concentration and volume of the diluted HCl solution, we can solve for V2:

0.09916 M x V1 = 0.04858 M x 0.101 L

V1 = 0.04858 M x 0.101 L / 0.09916 M = 0.04956 L

So, the volume of HCl solution used is 0.04956 L or 49.56 mL.

Step 2: Calculate the moles of Ac-. Using the concentration of Ac- in the buffer and the volume of HCl solution, we can calculate the moles of Ac-:

Moles of Ac- = [Ac-] x Volume of HCl solution

= 0.04858 M x 0.04956 L = 0.002407 mol

Therefore, the moles of Ac- in Solution C before the reaction took place is 0.002407.