Please calculate everything for sample 1 and show calculations so i could do res
ID: 590722 • Letter: P
Question
Please calculate everything for sample 1 and show calculations so i could do rest 3. Thank you i really appreciate that. Date: NAME: Partner: Pre-Lab Questions 1. Complete the calculations below based on the following student data. A student following the procedure in this lab prepared 4 solutions by adding 12.25, 23.00, 25.50, and 34.50 mL of a 8.25 x 10-2 M NaOH solution to 50.00 mL of a 0.152 M solution of weak acid. The solutions were labeled 1, 2,3, and 4 respectively. Each of the solutions was diluted to a total volume of 250 mL. with DI water. The pH readings of these solutions were: (1) 6.64 (2) 6.98 (3) 7.04 (4) 7.23 Sample 1 Sample 2 Sample 3 Sample 4 Initial number of moles of HAn and OH (before mixing) Show example calculation for trial 1 Here: HAn(aq) OH (ag) Number of moles at equilibrium after mixing Show example calculation for trial 1 Here 2 An (a) Equilibrium concentrations, mol/L Show example calculation for trial 1 Here: HAn(aq) An (aq) H30'(aq) Ka Average Ka Unknown weak acid from Table 1:Explanation / Answer
Titration
Calculations
Sample 1,
Initial moles before mixing,
HAn = 0.152 M x 50 ml = 7.6 mmol
OH- = 8.25 x 10^-3 M x 12.25 ml = 1.010625 mmol
After mixing moles at equilibrium,
pH = -log[H3O+] = 6.64
H3O+ = 2.3 x 10^-7 M
HAn = 7.6 - 1.010625 = 6.6 mmol
An- = 1.010625 mmol
Equilibrium concentrations in mol/L,
[HAn] = 66 mmol/250 ml = 0.0264 M
[An-] = 1.010625 mmol/250 ml = 4.0425 x 10^-3 M
[H3O+] = 2.3 x 10^-7 M
Ka = [H3O+][An-]/[HAn] = 3.52 x 10^-8