1 / 9

pH of Solutions

pH of Solutions. Experiment # 44. Introduction. Purpose: To find the pH of several common solutions, noting the range of the ph scale, to study the relationship between conjugate pairs of acids & bases the action of buffers. Introduction.

megan
Télécharger la présentation

pH of Solutions

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

Presentation Transcript

  1. pH of Solutions Experiment # 44

  2. Introduction • Purpose: • To find the pH of several common solutions, noting the range of the ph scale, • to study the relationship between conjugate pairs of acids & bases • the action of buffers

  3. Introduction • An acid solution results when the number of H+ ions exceeds the number oh OH- ions. When the number of H+ ions = OH- ions the solution is neutral. Universal Indicator neutral base acid 7 14 1 pink blue/purple green

  4. pH = - log [H+] • 0.01 Molarity HCl = 0.01 moles of H+ ions per Liter of solution [H+] x [OH-] = 1.0 x 10 -14 For all water solutions….. pH + pOH = 14 Example: [H+] = 10-9 , then [OH- ] = 10-5 pH = 9 pOH = 5

  5. pH Demo, Table 44-1 pH of Common substances Part 1, Demo Review Standardization of pH meters Part 2, Demo Part 3, Follow procedure in Lab Book Part 4, follow procedure

  6. Buffers & pH You will see how buffers resist large changes in pH. A buffer is usually a weak acid and its conjugate base. HC2H3O3 which can donate H + ions and lower pH and C2H3O3- which can accept a H+ ion. If the [OH-] of a solution is increased, the acid portion of a buffer system donates a H+ to neutralize the OH-. If the [H+] increases the conjugate base of the buffer will act to accept the H+ , so the pH will not change significantly. H+ OH- C2H3O3 - HC2H3O3

  7. Hydrolysis Objective : to see whether a salt reacts with water Hydrolysis is the cleavage ( lysis ) of water. When a + or - ion reacts with water to produce H+ or OH-, the pH changes. However not all ion react with water, if there is no reaction, the pH does not change. Part 4.

  8. Post Lab • Complete all Parts • Answer all questions • Use GA for graph of Part 3, A, pH vs Drops for water and buffer • Complete RX for table 44-1 on back of page 199

  9. HCl + H2O H3O+ + Cl - H20 + H2O H3O+ + OH - H20 + NH3 NH4+ + OH- H20 + NaOH Na+ + OH- Na+(HCO3-) + H2O H2CO3 + OH- Na2CO3 + H2O HCO3- + OH- NaCl + H2O Na + + Cl- +H2O NH4+ + OH- NH4 OH HC9H7O4 + H2O H3O+ + C9H7O4- RX

More Related