1 / 19

190 likes | 464 Vues

Bell Ringer. Which of the following aqueous solutions will cause litmus paper to turn red? A NaOH B NaCl C HCl D H 2 O. pH. 1-6. 7. 8-14. Solution Added. Acid. Neutral. Base. Litmus paper changes from. Blue to Red. Does not Change. Red to Blue. Source: 2003 VA EOC Exam.

Télécharger la présentation
## Bell Ringer

**An Image/Link below is provided (as is) to download presentation**
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.
Content is provided to you AS IS for your information and personal use only.
Download presentation by click this link.
While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

**Bell Ringer**Which of the following aqueous solutions will cause litmus paper to turn red? A NaOH B NaCl C HCl D H2O pH 1-6 7 8-14 Solution Added Acid Neutral Base Litmus paper changes from Blue to Red Does not Change Red to Blue Source: 2003 VA EOC Exam**pH**Ms. Besal 4/14/2006**A Quick Reminder…**• Reactions can stop at an EQUILIBRIUM NO2 + NO2 N2O4 Image source: http://cwx.prenhall.com**aA + bBcC + dD**(products) (reactants) The Equilibrium Constant, Keq For the reaction: • Where: • a, b, c, d are coefficients • A, B, C, D are substances [C]c[D]d Keq = [A]a[B]b [ ] = concentration in M**NO2 + NO2 N2O4**2 NO2 N2O4 The Equilibrium Constant, Keq For the reaction: [N2O4]1 [N2O4] Keq = = [NO2]1 [NO2]1 [NO2]2 [N2O4]1 [N2O4] Keq = = [NO2]2 [NO2]2**H2O + H2O H3O+ + OH-**A Special Equilibrium Constant, Kw For the reaction: [H3O+] [OH-] [H3O+] [OH-] = Kw = [H2O]2 “hydronium” “hydroxide” [1.00 x 10-7] [1.00 x 10-7] = 1.00 x 10-14 Kw = Image source: http://cwx.prenhall.com**Practice Problems**Using the knowledge that Kw = 1.00 x 10-14, solve for the missing piece of information: 1. Calculate the hydroxide ion concentration in a solution whose hydronium ion concentration is 1 x 10-5 M Kw = [H3O+] [OH-] 1.00 x 10-14 = [1 x 10-5 M] [OH-] [OH-] = 1.00 x 10-14 = 1 x 10-9 M 1 x 10-5 M**Practice Problems**2. Calculate the hydronium concentration for a solution whose hydroxide concentration is 0.0010 M. Kw = [H3O+] [OH-] 1.00 x 10-14 = [H3O+] [0.0010 M] [H3O+] = 1.00 x 10-14 = 1 x 10-11 M 0.0010M**Practice Problems**3. What is the hydroxide concentration of a solution if 0.080 grams of NaOH are dissolved in 2.0 L of solution? What is the hydronium ion concentration of this solution? 0.0010 M OH- 1.0 x 10-11 M H3O+ 1 mol NaOH 1 mol OH- 0.080 g NaOH 0.0020 mol OH- x x = 40.00 g NaOH 1 mol NaOH [OH-] = 0.0020 mol OH- = 0.0010 M OH- 2.0 L Kw = [H3O+] [OH-] 1.00 x 10-14 = [H3O+] [0.0010 M] [H3O+] = 1.00 x 10-14 = 1.0 x 10-11 M H3O+ 0.0010M**Practice Problems**4. What is the hydroxide ion concentration of a solution if 0.080 grams of Ca(OH)2 are dissolved in 2.0 L of solution? What is the hydronium ion concentration of this solution? 0.0020 M OH- 9.3 x 10-12 M H3O+ 1 mol Ca(OH)2 2 mol OH- 0.080 g Ca(OH)2 0.00216 mol OH- x x = 74.10 g Ca(OH)2 1 mol Ca(OH)2 [OH-] = 0.00216 mol OH- = 0.00108 M OH- 2.0 L Kw = [H3O+] [OH-] 1.00 x 10-14 = [H3O+] [0.00108 M] [H3O+] = 1.00 x 10-14 = 9.3 x 10-12 M H3O+ 0.00108M**pH – the POWER of H+!**These numbers represent the POWER of H+ pH = the negative logarithm of [H3O+] Image source: http://www.lowimpactdevelopment.org**Log-o-rhythms**Logarithm Exponent POWER = = pH – the POWER of H+! pH = the negative logarithm of [H3O+] POWER pH = - log [H3O+] Answer the following questions without using a calculator: • What is the pH of a solution with [H3O+] = 1.0 x 10-4 M? pH = 4.00 ACID • What is the pH of a solution with [H3O+] = 1.0 x 10-12 M? pH = 12.00 BASE**My Kingdom for a Calculator!**To solve for pH, given hydronium molarity • On TI-83: • push “(-)” key • push “log” key • type in number • On Scientific Calculators: • type in number • push “log” key • push +/- key**Practice Problems**1. What is the pH of a solution if the concentration of hydronium ions is 1.0 x 10-2 M? Is the solution acidic or basic? pH = - log [H3O+] pH = - log (1.0 x 10-2) pH = 2.00 ACIDIC SIG FIG RULES: Put the correct number of Sig Figs BEHIND the decimal point.**Practice Problems**2. What is the pH of a solution if the concentration of hydroxide ions is 1.0 x 10-4 M? Is the solution acidic or basic? Kw = [H3O+] [OH-] 1.00 x 10-14 = [H3O+] [1.0 x 10-4 M] [H3O+] = 1.00 x 10-14 = 1 x 10-10 M 1.0 x 10-4 M pH = - log [H3O+] pH = - log (1.0 x 10-10) pH = 10.00 BASIC**My Kingdom for a Calculator (again)!**To solve for hydronium molarity, given pH • On TI-83: • push “10x” key • push “(-)” key • type in pH • On Scientific Calculators: • type in number • push +/- key • push “2nd” key • push “log” key**Practice Problems**3. What is the concentration of hydronium ions in a solution whose pH is 8.00? pH = 8.00 = - log [H3O+] -8.00 = log [H3O+] 10–8.00 M = [H3O+] [H3O+] = 1.00 x 10-8 M**Practice Problems**4. For Question #3, what is the concentration of hydroxide ions? Kw = [H3O+] [OH-] 1.00 x 10-14 = [1.0 x 10-8 M] [OH-] [OH-] = 1.00 x 10-14 = 1 x 10-6 M 1.0 x 10-8 M**Practice Problems**5. What is the concentration of hydronium ions in a solution that has a volume of 2.50 L and 5.33 g of HCl? What is the pH of this solution? 1 mol HCl 1 mol H+ 5.33 g HCl 0.146 mol H+ x x = 36.46 g HCl 1 mol HCl [H+] = 0.146 mol H+ = 0.0584 M H+ 2.50 L pH = - log [H3O+] pH = - log (0.0584) pH = 1.234

More Related