1 / 29

Acids & Bases

Acids & Bases . Important Aqueous Solutions. NC Essential Standards. 3.2.1 Classify substances using the hydronium and hydroxide concentrations Distinguish between acids and bases based on formula and chemical properties

luka
Download Presentation

Acids & Bases

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. Acids & Bases Important Aqueous Solutions

  2. NC Essential Standards • 3.2.1 Classify substances using the hydronium and hydroxide concentrations • Distinguish between acids and bases based on formula and chemical properties • Differentiate between concentration (molarity) and strength (degree of dissociation) • Use pH to identify acids and bases. • Interpret pH scale in terms of the exponential nature of pH values in terms of concentrations. • Relate the color of indicator to pH using ranges provided in a table. • Compute pH, pOH, [H⁺] and [OH⁻] • 3.2.2 Distinguish properties of acids and bases related to taste, touch, reaction with metals, electrical conductivity, and identification with indicators such as litmus paper and phenolphthalein.

  3. Overview of Key Concepts • http://ed.ted.com/on/j4JlNr0Y#watch • Introduction 5 minutes

  4. Properties of acids and bases • http://ed.ted.com/lessons/the-strengths-and-weaknesses-of-acids-and-bases-george-zaidan-and-charles-morton Notes: Make 4 columns to easily jot down notes from the video • Acid propertiesBase properties Examples: StrongWeak Distinguish properties of acids and bases related to taste, touch, reaction with metals, electrical conductivity, and identification with indicators such as litmus paper and phenolphthalein. Note: Think H+ ions when protons are used.

  5. Review: Names and Formulas • Common acids that you must know • All are dissolved in water (aqueous solutions) • HCl • HBr • HF • HNO₃ • H₂SO₄ • HC₂H₃O₂ • H₂CO₃ • H₃PO₄

  6. Review: Names and Formulas • Common bases that you must know: • NaOH • Mg(OH)₂ • NH₃

  7. Acid & Base demonstrations • http://www.youtube.com/watch?v=ti_E2ZKZpC4 • Introduction - properties (5 minutes) • http://ed.ted.com/on/j4JlNr0Y

  8. Arrenhius Definition of Acids and Bases • Acids release H⁺ ion • Also known as hydronium ions (H₃O⁺) • Bases release OH⁻¹ (hydroxide) ions • Other definitions: • Bronsted Lowery • Lewis

  9. pH scale

  10. pH scale • pH values • pH = - log [H⁺]

  11. pH Scale Neutral ⇓

  12. Chemistry Reference TablesWhat do these formulas mean?

  13. Ions in Solutions Neutral [H⁺] [OH⁻] In water: [H⁺]= [ OH⁻] pH = 7 pOH = 7

  14. pOH Scale Neutral ⇓ Chemistry Reference Tables pH + pOH = 14

  15. Answers

  16. Examples of Acids and Bases

  17. pH Scale • http://www.johnkyrk.com/pH.html

  18. pH indicators • What is the approximate pH of the solution tested in the picture? Is the solution an acid or a base? Is it strong or weak?

  19. pH Indicators Litmus Paper Phenolphthalein Blue - indicates base Red - indicates acid

  20. pH Indicators - different indicators for different purposesScientist choose indicators based on the solution and process to be monitored.

  21. Universal Indicator Bromothymol Blue Acid = yellow Neutral = green Base = blue

  22. Strength of Acids and Bases • http://ed.ted.com/lessons/the-strengths-and-weaknesses-of-acids-and-bases-george-zaidan-and-charles-morton • 4 minutes • Write notes:

  23. Concentration⇎ Strength • Concentrated or dilute - Molarity • 6M vs. 0.6 M Strength or weak = degree to which acids or bases separate into ions

  24. Strength vs. Concentration • Strength in acids • Based on degree H⁺ ions separate from the anion • Proportion of acid molecules in which H⁺ separate compared to how many acid molecules do not separate • Strong acids = most H⁺ separate • Examples: HCl, HNO₃ and H₂SO₄ • Weak acids = only some H⁺ separate • Examples: HF, HC₂H₃O₂ • Strength of Bases • Strong = most OH⁻ separate from the metal

  25. Reacting acids and bases • HCl (aq) + Na(OH) (aq) → HOH + NaCl • Write the word formula • Identify the type of chemical reaction • What is happening with the reactants and products? • Ionic equation: • Solubility rules:

  26. Neutralization reactions • Special double replacement reaction • Always: • Reactants: Acid + Base (any order) • Products: Salt (ionic compound) + Water • Practice: • sulfuric acid and calcium hydroxide

  27. Neutralization reactions • Acid + Base → Salt + Water • sulfuric acid and calcium hydroxide • potassium hydroxide and nitric acid • carbonic acid and magnesium hydroxide • hydrobromic acid and lithium hydroxide

  28. Salts formed in the previous problems sulfuric acid and calcium hydroxide salt name: calcium sulfate salt formula: CaSO4 potassium hydroxide and nitric acid salt name: potassium nitrate salt formula: KNO3 carbonic acid and magnesium hydroxide salt name: magnesium carbonate salt formula: MgCO3 hydrobromicacid and lithium hydroxide salt name: lithium bromide salt formula: LiBr

More Related