Download presentation

Presentation is loading. Please wait.

Published byKarley Hammersley Modified over 4 years ago

1
Acid-Base Chemistry Tentative Test Date Monday, April 19 th Todays Objectives Distinguish among the three definitions of acids and bases. Calculate [H + ], [OH - ], and pH.

2
Definitions of Acids and Bases ACIDSBASES Arrhenius Proton Producer in Aqueous Solutions Hydroxide Producer in Aqueous Solutions Brønsted- Lowry Proton DonorProton Acceptor LewisElectron AcceptorElectron Donor More General Proton = H +

3
Identifying Acids and Bases For the following neutralization reactions, identify the acid and the base. 1) HF + H 2 O F - + H 3 O + 2) NH 3 + H 2 O NH 4 + + OH – Since water can act as both an acid and a base, it is called amphoteric. Acids = Lose H + Bases = Gain H + AcidBase Acid Base

4
Auto-Ionization of Water H 2 O(l) + H 2 O(l) H 3 O + (aq) + OH - (aq) hydronium ion hydroxide ion water molecule

5
Auto-Ionization of Water H 2 O(l) + H 2 O(l) H 3 O + (aq) + OH - (aq) K w = [H 3 O + ][OH - ] K w = Water Dissociation Constant At 25 o C, K w equals 1.0 x 10 -14. [H 3 O + ] = Concentration of H 3 O + [OH - ] = Concentration of OH -

6
Example Problem At 25 o C, the concentration of hydroxide ions in an aqueous solution is 4.5 x 10 -6 M. Determine the concentration of hydronium ions or [H 3 O + ]. K w = [H 3 O + ][OH - ] [H 3 O + ] == 2.2x10 -9 M [OH - ]

7
Simplified Equation H 2 O(l) + H 2 O(l) H 3 O + (aq) + OH - (aq) H 2 O(l) H + (aq) + OH - (aq) K w = 1.0 x10 -14 = [H + ][OH - ] H + and H 3 O + are interchangeable in the equation. Simplified

8
Now You Try A solutions hydrogen ion concentration is 9.01 x 10 -10 M. What is the concentration of hydroxide ions in this solution?

9
pH pH = - log [H + ] More Acidic More Basic

10
Simple pH Calculations Ex. #1:What is the pH of a solution with a hydronium ion concentration of 1.0 x10 -4 M? pH = -log[H 3 O + ] = - log (1.0x10 -4 M) = 4 Ex. #2: Calculate the pH of a solution if [H + ] equals 1.0x10 -9 M. pH = -log[H + ] = - log (1.0x10 -9 M) = 9 Which is more acidic: Example #1 or 2? Example #1 is more acidic since it has a lower pH.

11
pH with Log Tables Ex. #3:Calculate pH of 4.58 x 10 -3 M H +. pH = - log [H + ] pH = - log (4.58 x 10 -3 M) pH = - [log (4.58) + log (10 -3 )] pH = -[0.661 + -3] = - [ -2.339] pH = 2.339

12
pH with Log Tables Ex. #3:Calculate pH of a solution if the hydronium ion concentration is 1.79 x 10 -8 M. pH = - log [H 3 O + ] pH = - log (1.79 x 10 -8 M) pH = - [log (1.79) + log (10 -8 )] pH = -[0.253 + -8] = - [ -7.647] = 7.647

13
Homework Lab notebooks due tomorrow!! Worksheet on Naming and Writing Formulas for Acids and Bases Book Problems pg. 582 # 6 & 7 pg. 586 # 8 & 9

14
Acid-Base Chemistry Tentative Test Date Monday, April 19 th Todays Objective Calculate [H + ], [OH - ], pH and pOH.

15
Review from Yesterday Calculate the pH of a solution whose hydronium ion concentration is 2.71 x 10 -7 M. pH = - log (2.71 x 10 -7 M) pH = -[log (2.71) + log (10 -7 )] pH = - [0.433 + -7] pH = 6.567

16
Combining the Problems Using your calculator, calculate the pH of a solution whose hydroxide ion concentration is 1.3 x 10 -3 M. Step 1: Find [H + ]. Step 2: Calculate pH. pH = -log (7.69 x 10 -12 M) pH = - [log (7.69) + log (10 -12 )] pH = -[0.886 + -12] pH = 11.114

17
Relationships between pH, [H 3 O + ], and [OH - ] As pH increases… The solution becomes more (acidic or basic). The [H 3 O + ] (increases or decreases). The [OH - ] (increases or decreases).

18
[H + ] from pH pH = -log[H + ] -pH = log[H + ] 10 You will either need to be able to derive this formula or memorize this formula.

19
[H + ] from pH Ex #1: Calculate the hydronium ion concentration for a solution with a pH of 6.719. [H + ] = 10 –pH = 10 –6.719 Using the Log Tables, 10 -6.72 = 10 -7 x 10 0.281 1.91 x 10 -7 M From Log Tables

20
[H + ] from pH Ex #2: Calculate the hydronium ion concentration for a solution with a pH of 10.5. [H + ] = 10 –pH = 10 –10.5 Using Your Calculator, press the following buttons for most calculators. 2 nd Log – 10.5 3.16 x 10 -11 M

21
pOH pOH = -log [OH - ] Using your log tables, calculate the pOH of a solution that contains 0.0807 M OH -. 0.0807 M = 8.07 x 10 -2 M pOH = - log (8.07x10 -2 M) = -[log (8.07) + log(10 -2 )] pOH = -[0.907 + -2] = 1.093

22
Relating pH and pOH K w = [H + ][OH - ] 1.0x10 -14 = [H + ][OH - ] -log(1.0x10 -14 ) = -log([H + ][OH - ]) -log(1.0x10 -14 ) = -log[H + ] + -log[OH - ] 14 = pH + pOH

23
A Summary of Calculations Important Formulas K w = [H + ][OH - ]pH + pOH = 14 pH = -log[H + ][H + ] = 10 -pH pOH = -log[OH - ] [OH - ] = 10 -pOH Types of SolutionpH[H + ] vs [OH - ] AcidicLess than 7[H + ] > [OH - ] Neutral7.000…[H + ] = [OH - ] BasicGreater than 7[H + ] < [OH - ]

Similar presentations

OK

Warm Up 4/14 How many protons and neutrons would an H+ ion have?

Warm Up 4/14 How many protons and neutrons would an H+ ion have?

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google