The results of Exercises 19-21 illustrate an important...

Name: Problem 22, Chapter 8: Chemical Principles
Uploaded: 2020-09-13T03:21:58-08:00
Duration: 4 min 48 s
Channel: Susan Hallstrom
Description: The results of Exercises 19-21 illustrate an important property of buffered solutions. Which solution in Exercise 19 is the buffered solution and what important property is illustrated by the results?

The results of Exercises 19-21 illustrate an important property of buffered solutions. Which solution in Exercise 19 is the buffered solution and what important property is illustrated by the results?

Key Concepts

pH Stability of Buffer Systems

The important property illustrated by the results is the buffered solution’s ability to resist changes in pH when small amounts of acid or base are added. This characteristic is central to buffer systems, as it enables them to maintain a near-constant pH, which is crucial in many chemical, biological, and industrial processes where pH stability is necessary.

Buffered Solution

A buffered solution is one that contains significant amounts of both a weak acid and its conjugate base (or a weak base with its conjugate acid). This combination allows the solution to neutralize added acids or bases, thereby maintaining a relatively constant pH. In the context of the exercise, the buffered solution is the one formulated with these two components in appreciable concentrations, which is designed to resist drastic pH changes upon the addition of other substances.

Transcript

00:01 This problem asked us to consider the last three problems that were solved.

00:06 We were asked to find the ph of four different solutions, barely four solutions because one was water.

00:18 Then we were asked to find the ph after adding hcl, and then we were asked to find the ph after adding n -a -o -h.

00:29 And it was all the same solutions.

00:39 This is a voiceover.

00:49 Pure water is the easy one.

00:51 We're asked to, let me see, what are we asked to do? which one is the buffered solution? well, we know it's not the pure water.

01:01 And we're given, for the first solution, which is one on the top, we're given propanoic acid, and then we're given nac3h5, that should be o2.

01:15 And the third one is a combination, excuse me, the fourth one is a combination of a weak acid and its conjugate base.

01:26 So this one that's highlighted is the buffered solution.

01:40 And what is the important property indicated by this? the important property is that we can add, i'm going way back there, i have no idea what i was doing there.

02:11 Sorry about that this is the original problem that we were doing before we added any acid or base.

02:17 So we're looking at what happens when we add acid and base to the buffered solution, which is the last one.

02:27 There was a buffered solution that was 4 .71, and now for a buffered solution it was 0 .506.

02:54 So for this question, what are they asking me there? oh, that was the ph when we added the acid and then we added the base...

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