Download presentation

Presentation is loading. Please wait.

2
**Friday, May 6th: “A” Day Agenda**

Homework questions/problems/collect Quiz over section 15.2: “Acidity, Basicity, and pH” Section 15.3: “Neutralizations and Titrations” Neutralization reaction, equivalence point, titration, titrant, standard solution, transition range, end point Homework: Sec review, pg. 556: #1-10 Concept Review: “Neutralizations and Titrations” Lab Write-Up: “Titration of an Acid and a Base”

3
**Section 15.2 Quiz “Acidity, Basicity, and pH”**

You may use your guided notes, your book, and a partner to complete the quiz.

4
**H3O+(aq) + OH−(aq) 2 H2O(l)**

Neutralization Neutralization reaction: the reaction of hydronium ions and hydroxide ions to form water molecules and a salt. When solutions of a strong acid and a strong base, having exactly equal amounts of H3O+(aq) and OH−(aq) ions, are mixed, almost all of the hydronium and hydroxide ions react to form water. H3O+(aq) + OH−(aq) 2 H2O(l) *correct*

5
Neutralization Suppose that hydrochloric acid, HCl, and sodium hydroxide, NaOH are mixed. The result will be a solution of only water and the spectator ions sodium and chlorine. This is just a solution of sodium chloride. HCl + NaOH NaCl + H2O This representation can be misleading because the only reactants are H3O+(aq) and OH−(aq) ions and the only product is H2O.

6
Titrations If an acidic solution is added gradually to a basic solution, at some point the neutralization reaction ends because the hydroxide ions are used up. Likewise, if a basic solution is added to an acid, eventually all of the hydronium ions will be used up. The point at which a neutralization reaction is complete is known as the equivalence point. Equivalence point: the point at which the two solutions used in a titration are present in chemically equivalent amounts.

7
Titrations When a solution of a strong base is added to a solution of a strong acid, the equivalence point occurs when the amount of added hydroxide ions equals the amount of hydronium ions originally present. Titration: the gradual addition of one solution to another to reach an equivalence point. The purpose of a titration is to determine the concentration of an acid or a base.

8
Titration In addition to the two solutions, the equipment needed to carry out a titration usually includes two burets, a titration flask, and a suitable indicator. One buret is for the acid solution, the other is for the basic (alkaline) solution. Titrant: a solution of known concentration that is used to titrate a solution of unknown concentration.

9
Titration To find the concentration of the solution being titrated, you must already know the concentration of the titrant. Standard solution: a solution of known concentration. The concentration of a standard solution has usually been determined by reacting the solution with a precisely weighed mass of a solid acid or base.

10
Titration A distinctively shaped graph, called a titration curve, results when pH is plotted against titrant volume. Because the curve is steep at the equivalence point, it is easy to locate the exact volume that corresponds to a pH of 7.00. A titration is exact only if the equivalence point can be accurately detected.

11
Equivalence Point This graph of pH versus the volume of M NaOH added to an HCl solution indicates that the equivalence point occurred after 38.6 mL of titrant was added.

12
Indicators Transition range: the pH range through which an indicator changes color. End point: the point in a titration at which a marked color change takes place. If an appropriate indicator is chosen, the end point and the equivalence point will be the same.

13
**Selecting an Indicator**

In titrations of a strong acid by a strong base, the equivalence point occurs at pH 7. When a weak acid is titrated by a strong base, the equivalence point is at a pH greater than 7. The titration of a weak base and a strong acid, the equivalence point is at a pH less than 7.

14
**How to Perform a Titration**

15
**How to Perform a Titration**

16
**Titration Calculations**

At the equivalence point in a titration of a strong acid by a strong base, the amount of hydroxide ion added equals the initial amount of hydronium ion. C: concentration (in moles per liter) V: volume (in liters) of the solution

17
**Titration Calculations**

An easier way to think of this: (C Acid)(V Acid) = (C Base) (V Base) C: concentration (in moles per liter) V: volume (in liters) of the solution

18
**(CAcid) (VAcid) = (CBase) (VBase)**

Sample Problem D, pg. 555 Calculating Concentration from Titration Data A student titrates mL of an HCl solution of unknown concentration with a M NaOH solution. The volume of base solution needed to reach the equivalence point is mL. What is the concentration of the HCl solution in moles/liter? (CAcid) (VAcid) = (CBase) (VBase)

19
**Sample Problem D, continued…**

NaOH is a strong base so: NaOH Na + + OH- M M C(acid) = ? V(acid) = mL = .04L C(base) = M V(base) = mL = L (CAcid) (VAcid) = (CBase) (VBase) C (Acid) (.04 L) =( M) ( L) C(acid) = mol/L

20
Additional Practice If 72.1 mL of M H2SO4 completely titrates 39.0 mL of KOH solution, what is the molarity of the KOH solution? H2SO4 is a strong acid so: H2SO H2O SO H3O + 0.543 M M Because of the 1:2 ratio, 1 mole of H2SO4 makes 2 moles of H3O +. [H3O+] = 2 [H2SO4] = 2 (0.543 M) = M

21
**Additional Practice, continued…**

(CAcid) (VAcid) = (CBase) (VBase) C(acid) = M V(acid) = 72.1 mL = L C(base) = ? V(base) = 39.0 mL = L (1.086 M) (.0721 L) = (C Base) (.0390L) C(base) = 2.01 M

22
**U of I 3D-Printing Presentation on Tuesday! Titration lab on Thursday**

Homework Section 15.3 review, pg. 556: #1-10 Concept Review: “Neutralizations and Titrations” Lab Write-Up: “Titration of an Acid and a Base” Looking Ahead: U of I 3D-Printing Presentation on Tuesday! Titration lab on Thursday No Flip-Flops!

Similar presentations

OK

Steps in preparing a solution of known molar concentration: 250 mL 1) Decide how much (volume) solution you want to make and what concentration (Molarity)

Steps in preparing a solution of known molar concentration: 250 mL 1) Decide how much (volume) solution you want to make and what concentration (Molarity)

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on atomic structure class 11 Ppt on fire alarm project Ppt on hindu religion books Ppt on product advertising ideas Ppt on rag picking Ppt on job evaluation Ppt on biodegradable and non biodegradable resources Ppt on conservation of momentum equation Ppt on diodes and transistors for sale Ppt on maggi advertisement