Docsity
Docsity

Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity


Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan


Guidelines and tips
Guidelines and tips

Titration Curves: Understanding pH Changes in Acid-Base Reactions, Study notes of Stoichiometry

An introduction to titration curves, explaining the concept of pH changes during acid-base titrations and the significance of equivalence and endpoint points. It covers three types of titration reactions: strong acid and strong base, weak acid and strong base, and strong acid and weak base. The document also includes instructions on choosing indicators and matching titration curves with reactions.

Typology: Study notes

2021/2022

Uploaded on 09/12/2022

myboy
myboy 🇺🇸

4.4

(72)

260 documents

1 / 10

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
TITRATION CURVES
UNIT 5 CH40S WIEBE
pf3
pf4
pf5
pf8
pf9
pfa

Partial preview of the text

Download Titration Curves: Understanding pH Changes in Acid-Base Reactions and more Study notes Stoichiometry in PDF only on Docsity!

TITRATION CURVES

UNIT 5 CH40S WIEBE

A titration curve is a graph of the pH changes that occur during an acid-

base titration versus the volume of acid or base added.

The equivalence point is the end of a titration where the stoichiometry

of the reaction is exactly satisfied, or moles H

+ = moles OH

- .

The end point refers to when an indicator changes color and [HInd] =

[Ind

- ].

Titration Curves

When you choose an indicator, you must pick one so that the transition

point of the indicator matches the equivalence point of the titration.

Rule of thumb Dominant Equivalence Point

Neither 7

Base 9

Acid 5

Choosing an Indicator

  1. Titration Curve: Strong Acid and Strong Base

HCl + KOH → KCl + HOH

Endpoint pH = 7 Bromothymol Blue- see page 7

50 mL of 0.10 M KOH is added to 25 mL of 0.10 M HCl

pH

Volume .10 M KOH added

14

7

0

0 25 50

0.10 M HCl

Endpoint pH = 7.

0.10 M KOH

We start here

The pH of 0.10 M HCl is 1. The pH of 0.10 M KOH is 13.

  1. Titration Curve: Strong Acid and Weak Base

HCl + NH 3

→ NH

4

  • Cl
  • strong acid dominates!

Endpoint pH ~ 5 Methyl Red- see page 7

60 mL of 1.0 M NH 3

is added to 30 mL of 1.0 M HCl

pH

Volume 1.0 M NH 3

added

14

7

0

0 30 60

1.0 M HCl pH = 0

Endpoint pH  5

1.0 M NH

3

pH  10 (weak base)

pH

Volume .10 M KOH added

14

7

0

0 25 50

  1. Match the Curve with the Reaction

A. HCl + NH 3

→ NH

4

  • Cl

B. HCl + KOH → KCl + HOH

C. HCN + KOH → KCN + HOH

pH

Volume 1.0 M NH 3

added

14

7

0

0 30 60

6. Match the Curve with the Reaction

A. HCl + NH 3

→ NH

4

  • Cl

B. HCl + KOH → KCl + HOH

^ C.^ HCN^ +^ KOH^ →^ KCN^ +^ HOH