Purchase Solution

Buffer cacluation without Hasselbach

Not what you're looking for?

Ask Custom Question

Find the solutions without using the Henderson-Hasselbalch equation. Please show all calculations.

Question #1

A student dissolves 0.25 moles of the acid HA in water and dilutes the solution to the final volume of 500 mL. The student then gives a small portion of the solution to her professor. The professor uses a pH meter and finds the solution given to him has a pH of 0.96

a) Find the H+ in the solution
b) Find the Ka (Ionization constant)

Question #2

A student mixes 3.0 mL of 0.20 M NH3 (aq) with 70.0 mL of 0.30 M NH4CL(aq). Find H+ in the solution Kb = 1.8 X10^-5.

Question #3

A student adds a certain number of moles of NH3 to 100 mL of a 0.4 MNH4CL(aq) solution and finds the resulting solution has H+ = 8.3 x 10^- M. How many moles of NH3 were added (assume the final solution volume is still 100 mL. Kb = 1.8 x 10^-5)?

Question #4

Which one of the following gives a buffer solution?

a) 50 Ml of 0.1 M HCl (aq) mixed with 80 mL of 0.1 M NaOH (aq).
b) 80 Ml of 0.1 M HCl (aq) mixed with 50 mL of 0.1 M NaOH (aq).
c) 50 Ml of 0.1 M HC2H3O2 (aq) mixed with 50 mL of 0.1 M NaOH (aq).
d) 50 Ml of 0.1 M HC2H3O2 (aq) mixed with 80 mL of 0.1 M NaOH (aq).
e) 80 Ml of 0.1 M HC2H3O2 (aq) mixed with 500 mL of 0.1 M NaOH (aq).
f) None of the above

Purchase this Solution

Solution Summary

A few buffer problems are solved without using the Henderson-Hasselbach equation.

Solution Preview

Q1. pH = -log[H+]. Hence [H+] = 10^(-pH) = 10^(-0.96) = 0.11M

Initial concentration of HA = 0.25 mol / 0.5L = 0.5M

Ka = [H+][A-] / [HA] = 0.11 x 0.11 / (0.5 - 0.11) = 3.10 x 10^(-2)

Q2. [NH3] = (0.003 x 0.2) / 0.073 = 0.00822M

[NH4+] = 0.07 x 0.30 / 0.073 = 0.288M

NH3 + ...

Purchase this Solution


Free BrainMass Quizzes
Thermochemistry

The quiz helps in revising basic concepts about thermochemistry.

General Chemistry - Classification of Matter

This test will assess your knowledge on the classification of matter which includes elements, compounds and mixtures.

Organic Chemistry Naming: Alkanes

This is a quiz which is designed to assist students with learning the nomenclature used to identify organic compounds. This quiz focuses on the organic compounds called Alkanes.

Match Elements with their Symbols

Elements are provided: choose the matching one- or two-letter symbol for each element.