Download presentation

Presentation is loading. Please wait.

Published byMustafa Platner Modified over 3 years ago

1
1 Chapter 14 Acids and Bases 14.6 The pH Scale Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

2
2 pH Scale The pH scale: Is used to indicate the acidity of a solution. Has values that usually range from 0 to 14. Is acidic when the values are less than 7. Is neutral with a pH of 7. Is basic when the values are greater than 7.

3
3 pH of Everyday Substances Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

4
4 Identify each solution as 1. acidic 2. basic3. neutral A. ___ HCl with a pH = 1.5 B. ___ Pancreatic fluid [H 3 O + ] = 1 x 10 −8 M C. ___ Sprite soft drink pH = 3.0 D. ___ pH = 7.0 E. ___ [OH − ] = 3 x 10 −10 M F. ___ [H 3 O + ] = 5 x 10 −12 Learning Check

5
5 A. 1 HCl with a pH = 1.5 B. 2 Pancreatic fluid [H 3 O + ] = 1 x 10 −8 M C. 1 Sprite soft drink pH = 3.0 D. 3 pH = 7.0 E. 1 [OH - ] = 3 x 10 −10 M F. 2 [H 3 O + ] = 5 x 10 −12 Solution

6
6 Testing the pH of Solutions The pH of solutions can be determined using pH meter, pH paper, or indicators that have specific colors at different pH values. Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

7
7 pH Range Table 14.8 Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

8
8 pH is the negative log of the hydronium ion concentration. pH = - log [H 3 O + ] For a solution with [H 3 O + ] = 1 x 10 −4 pH =−log [1 x 10 −4 ] pH = - [-4.0] pH = 4.0 Calculating pH

9
9 Significant Figures in pH When expressing log values, the number of decimal places in the pH is equal to the number of significant figures in the coefficient of [H 3 O + ]. [H 3 O + ] = 1 x 10 -4 pH = 4.0 [H 3 O + ] = 8.0 x 10 -6 pH = 5.10 [H 3 O + ] = 2.4 x 10 -8 pH = 7.62

10
10 Guide to pH Calculations Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

11
11 Find the pH of a solution with a [H 3 O + ] of 1.0 x 10 −3 : STEP 1 Enter [H 3 O + ] Enter 1 x 10 -3 by pressing 1 (EE) 3 The EE key gives an exponent of 10 and change sign (+/- key or – key) STEP 2 Press log key and change sign - log (1 x 10 −3 ) = -[-3] STEP 3 Adjust significant figures after decimal point 3 3.00 Two significant figures in 1.0 x 10 −3 Calculating pH

12
12 A. The [H 3 O + ] of tomato juice is 2 x 10 −4 M. What is the pH of the solution? 1) 4.02) 3.73) 10.3 B. The [OH − ] of a solution is 1.0 x 10 −3 M. What is the pH of the solution? 1) 3.002) 11.003) -11.00 Learning Check

13
13 A. 2) 3.7 pH = - log [ 2 x 10 -4 ] = 3.7 2 (EE) 4 (+/-) log (+/-) B. 2) 11.00 Use the K w to obtain [H 3 O + ] = 1.0 x 10 −11 pH = - log [1.0 x 10 −11 ] 1.0 (EE) 11 (+/-) log (+/-) Solution

14
14 pOH The pOH of a solution Is analogous to the pH value on the pH scale. Is based on the [OH − ]. Has high pOH values with low [OH − ] and high [H 3 O + ]. Is equal to the - log [OH - ] pOH = - log [OH - ]. Added to the pH value is equal to 14.0. pH + pOH = 14.0

15
15 Calculation pOH Find the pOH of a solution with a [OH − ] of 2.0 x 10 −3. STEP 1 Enter [OH − ] STEP 2 Press log key and change sign - log (2.0 x 10 −3 ) = -[-2.69897] = 2.69897 STEP 3 Adjust figures after decimal point 2.70 Two significant figures in 2.0 x 10 −3

16
16 Calculating [H 3 O + ] from pH The [H 3 O + ] can be expressed by using the pH as the negative power of 10. [H 3 O + ] = 1 x 10 −pH If the pH is 3.0, the [H 3 O + ] = 1 x 10 −3 On a calculator 1. Enter the pH value 3.0 2. Change sign -3.0 3. Use the inverse log key (or 10 x ) to obtain the [H 3 0 + ]. =1 x 10 −3 M

17
17 A. What is the [H 3 O + ] of a solution with a pH of 10.0? 1) 1 x 10 −4 M2) 1 x 10 10 M 3) 1 x 10 −10 M B. What is the [H 3 O + ] of a solution with a pH of 5.75? 1) 1.8 x 10 − 6 M2) 1.778 x 10 −6 M 3) 2 x 10 −6 M Learning Check

18
18 A. What is the [H 3 O + ] of a solution with a pH of 10.0? 3) 1 x 10 -10 M1 x 10 -pH B. What is the [H 3 O + ] of a solution with a pH of 5.75? 1) 1.8 x 10 − 6 M 5.75 (+/-) inv log (or 10 x ) = 1.8 x 10 -6 Note: Two decimal places (.75), indicate two significant figures in the coefficient of the answer. Solution

19
19 Learning Check What is the pH and the pOH of coffee if the [H 3 O + ] is 1 x 10 −5 M? 1) pH = 5.0 pOH =7.0 2) pH = 7.0 pOH = 9.0 3) pH = 5.0pOH = 9.0

20
20 Solution What is the pH and the pOH of coffee if the [H 3 O + ] is 1 x 10 −5 M? 3) pH = 5.0pOH = 9.0 pH = -log [1 x 10 −5 ] = -(-5.0) = 5.0 pH + pOH = 14.0 pOH = 14.0 – pH = 14.0 – 5.0 = 9.0 or [OH - ] = 1 x 10 −9 pOH = - log [1 x 10 −9 ] = -(-9.0) = 9.0

Similar presentations

OK

MULT. INTEGERS 1. IF THE SIGNS ARE THE SAME THE ANSWER IS POSITIVE 2. IF THE SIGNS ARE DIFFERENT THE ANSWER IS NEGATIVE.

MULT. INTEGERS 1. IF THE SIGNS ARE THE SAME THE ANSWER IS POSITIVE 2. IF THE SIGNS ARE DIFFERENT THE ANSWER IS NEGATIVE.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on antibiotic resistance mechanism Ppt on ram and rom computer Ppt on time management at workplace Ppt on world diabetes day theme Free ppt on mobile number portability solutions Ppt on solar based ups system Ppt on any one mathematician paul Ppt on art and craft movement Topics for ppt on environmental management Ppt on javascript events handling