1 / 26

Definition of Acid & Base

Definition of Acid & Base. Arrhenius Acid: substance that produces H + ions Base: substance that produces OH - ions Bronsted & Lowry Acid: substance that donates a proton to another substances Base: substance that accepts a proton to another substances.

bart
Download Presentation

Definition of Acid & Base

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. Definition of Acid & Base • Arrhenius • Acid: substance that produces H+ ions • Base: substance that produces OH- ions • Bronsted & Lowry • Acid: substance that donates a proton to another substances • Base: substance that accepts a proton to another substances

  2. Acids - A Group of Covalent Molecules Which Lose Hydrogen Ions to Water Molecules in Solution When gaseous hydrogen iodide dissolves in water, the attraction of the oxygen atom of the water molecule for the hydrogen atom in HI is greater that the attraction of the of the iodide ion for the hydrogen atom, and it is lost to the water molecule to form an hydronium ion and an iodide ion in solution. We can write the hydrogen atom in solution as either H+(aq) or as H3O+(aq) they mean the same thing in solution. The presence of a hydrogen atom that is easily lost in solution is an “Acid” and is called an “acidic” solution. The water (H2O) could also be written above the arrow indicating that the solvent was water in which the HI was dissolved. HI(g) + H2O(L) H+(aq) + I -(aq) HI(g) + H2O(L) H3O+(aq) + I -(aq) H2O HI(g) H+(aq) + I -(aq)

  3. Figure 4.8B: Red cabbage juice added to solutions in the beakers.Photo courtesy of James Scherer.

  4. Reaction of nitric acid with water. HNO3(aq)+ H2O(l)  NO3-(aq) + H3O+(aq)

  5. Molecular representation of ammonium hydroxide. NH3(aq) + H2O(l) NH4+(aq) + OH-(aq)

  6. Strong Acid or Base An acid or base that ionizes completely in water. It is present entirely as ions; it is a strong electrolyte.

  7. Weak Acid or Base • An acid or base that is only partly ionized in water. It is present primarily as molecules and partly as ions; it is a weak electrolyte. Weak bases are often nitrogen bases such as NH3: • NH3(aq) + H2O(l) →NH4+(aq) + OH-(aq) • The most common weak acid is acetic acid: • HC2H3O2 (aq)+ H2O(l) → H3O+(aq)+ C2H3O2-(aq) • If an acid or base is not strong, it is weak.

  8. Polyprotic Acid • An acid that results in two or more acidic hydrogens per molecule • For example: H2SO4, sulfuric acid

  9. Neutralization Reaction • A reaction of an acid and a base that results in an ionic compound (a salt) and possibly water • Write the molecular, ionic, and net ionic equations for the neutralization of sulfurous acid, H2SO3, by potassium hydroxide, KOH. Sulfurous acid is a WEAK acid.

  10. Molecular Equation • (Balance the reaction and include state symbols) • H2SO3(aq) + 2KOH(aq)  2H2O(l) + K2SO3(aq) • Ionic Equation • H2SO3(aq) + 2K+(aq) + 2OH-(aq)  • 2H2O(l) + 2K+(aq) + SO32-(aq) • Net Ionic Equation • H2SO3(aq) + 2OH-(aq)  2H2O(l) + SO32-(aq)

  11. Acid-Base Reaction with Gas Formation • Some salts, when treated with an acid, produce a gas. Typically sulfides, sulfites, and carbonates behave in this way producing hydrogen sulfide, sulfur trioxide, and carbon dioxide, respectively. The photo shows baking soda (sodium bicarbonate) reacting with acetic acid in vinegar to give bubbles of carbon dioxide. Write the reaction that’s occurring.

  12. Molarity (Concentration of Solutions)= M Moles of Solute Moles Liters of Solution L M = = solute = material dissolved into the solvent In air , Nitrogen is the solvent and oxygen, carbon dioxide, etc. are the solutes. In sea water , Water is the solvent, and salt, magnesium chloride, etc. are the solutes. In brass , Copper is the solvent (90%), and Zinc is the solute(10%)

  13. Fig. 3.11

  14. Preparing a Solution - I • Prepare a solution of Sodium Phosphate by dissolving 3.95g of Sodium Phosphate into water and diluting it to 300.0 ml or 0.300 l ! • What is the Molarity of the salt and each of the ions? • Na3PO4 (s) + H2O(solvent) = 3 Na+(aq) + PO4-3(aq)

  15. You place a 1.62-g of potassium dichromate, K2Cr2O7, into a 50.0-mL volumetric flask. You then add water to bring the solution up to the mark on the neck of the flask. What is the molarity of K2CrO7 in the solution? Molar mass of K2Cr2O7 is 294 g. 0.110 M

  16. Dilution • When a higher concentration solution is used to make a less-concentration solution, the moles of solute are determined by the amount of the higher-concentration solution. The number of moles of solute remains constant. • MiVi = MfVf • Note: • The units on Vi and Vf must match.

  17. A saturated stock solution of NaCl is 6.00 M. How much of this stock solution is needed to prepare 1.00-L of physiological saline soluiton (0.154 M)?

  18. Titration • A procedure for determining the amount of substance A by adding a carefully measured volume with a known concentration of B until the reaction of A and B is just complete

  19. Figure 4.22C: Titration of an unknown amount of HCl with NaOH (#3). Photo courtesy of American Color.

  20. Titration of an unknown amount of HCl with NaOH. • In the titration above, the indicator changes color to indicate when the reaction is just complete.

  21. Zinc sulfide reacts with hydrochloric acid to produce hydrogen sulfide gas: • ZnS(s) + 2HCl(aq) ZnCl2(aq) + H2S(g) • How many milliliters of 0.0512 M HCl are required to react with 0.392 g ZnS?

  22. Molar mass of ZnS = 97.47 g • = 0.157 L = 157 mL HCl solution

More Related