1 / 38

Acids & Bases

Acids & Bases. They are everywhere.. In your food In your house EVEN IN YOU!!!!!. What is an acid?. An acid is a solution that has an excess of H+ ions. It comes from the Latin word acidus that means "sour". The more H + or H 3 O + ions, the more acidic the solution.

kunknow
Télécharger la présentation

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 They are everywhere.. In your food In your house EVEN IN YOU!!!!!

  2. What is an acid? • An acid is a solution that has an excess of H+ ions. It comes from the Latin word acidus that means "sour". • The more H+ or H3O+ ions, the more acidic the solution. • Also known as Arrehenius Acid • According to the “other theory” a proton (H+) donor

  3. Properties of an Acid • Tastes Sour • Conduct Electricity • Corrosive, which means they break down certain substances. Many acids can corrode fabric, skin,and paper • Some acids react strongly with metals • Turns blue litmus paper red Picture from BBC Revision Bites http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_bases_1.shtml

  4. Uses of Acids • Acetic Acid = Vinegar • Citric Acid = lemons, limes, & oranges. It is in many sour candies such as lemonhead & sour patch. • Ascorbic acid = Vitamin C which your body needs to function. • Sulfuric acid is used in the production of fertilizers, steel, paints, and plastics. • Car batteries

  5. What is a base? • A base is a solution that has an excess of OH- ions. • Another word for base is alkali. • Bases are substances that can accept hydrogen ions • Also known as Arrehenius base • According to the “Other theory” a Proton (H+) acceptor

  6. Properties of a Base • Feel Slippery • Taste Bitter • Corrosive • Can conduct electricity. (Think alkaline batteries.) • Do not react with metals. • Turns red litmus paper blue.

  7. Uses of Bases • Bases give soaps, ammonia, and many other cleaning products some of their useful properties. • The OH- ions interact strongly with certain substances, such as dirt and grease. • Chalk and oven cleaner are examples of familiar products that contain bases. • Your blood is a basic solution.

  8. Rules and Exceptions • Always check tables to see if substance is acid or base • Most acids have H in front • (except CO2) • Most bases have OH at end • (except NH3 and hydrocarbons followed by OH)

  9. Not an acid, base or salt 2 nonmetals (covalent bonds) CH4 NO2 and alcohols: CH3OH, (methanol) CH3CH2OH (ethanol) This OH is NOT a BASE!!! (It’s an alcohol) Organic acids: vinegar (acetic acid) CH3COOH also written HC2H3O2

  10. Vocabulary • Electrolytes • Indicator • Salt • Conducts electricity b/c of mobile ions (acid,base,salt)ABS • Substance that changes color in acids and bases • Metal + nonmetal or polyatomic ion but NO “H” or “OH” ( ionic bond)ex. NaCl Na+ + Cl-

  11. Practice: Label the following as either: acid, base, salt, neither • HNO3 • LiOH • LiCl • KOH • HCl • NaNO3 • C3H8 • HI • CuCl2 • Ca(OH)3 • Mg(OH)3 • H3PO4 • KBr • FeI2 • C6H12O6 • NH3(aq) • CO2(aq) • CH3CH2OH

  12. pH Scale • pHis a measure of how acidic or basic a solution is. • The pH scale ranges from 0 to 14. • Acidic solutions have pH values below 7 • A solution with a pH of 0 is very acidic. • A solution with a pH of 7 is neutral. • Pure water has a pH of 7. • Basic solutions have pH values above 7.

  13. pH Scale • A change of 1 pH unit represents a tenfold change in the acidity of the solution. • For example, if one solution has a pH of 1 and a second solution has a pH of 2, the first solution is not twice as acidic as the second—it is ten times more acidic.

  14. Acid – Base Reactions • A reaction between an acid and a base is called neutralization. An acid-base mixture is not as acidic or basic as the individual starting solutions. • acid + base  salt + water • H+(aq) + OH-(aq)  HOH • (HOH is H2O)

  15. The “Other Theory” • BAAD • Bases accept, acids donate • Acids • Proton (H+) donor • Bases • Proton (H+) acceptor • Example: • HCl + NH3 NH4+ + Cl- Acid Base Acid Base

  16. Each pH unit is 10times as large as the previous one A change of 2 pH units means 100 times more basic or acidic x10 x100 The pH Scale

  17. Weak acid, strong base Strong Acid Weak acid/base Strong Base Increasing H+ ions (H3O+) Increasing OH- ions (hydrogen/hydronium ions) (hydroxide ions)

  18. 10 fold increase, 1/10 decrease OH- increases 10 fold, H3O+ decreases 1/10 H3O+ increases 10 fold, OH- decreases 1/10

  19. Neutralization reactions • Are also double replacement reactions • Acid + base  salt + water • Outer ions combine, inner ions combine • HCl + NaOH NaCl + H2O • H2SO4 + 2KOH  K2SO4 + 2H2O

  20. Example: Stomach antacids

  21. Practice • 2. Complete and balance the following equations representing neutralization reactions: • 2 CsOH + H2CO3 • 2 HF + Mg(OH)2 • 3 HNO3 + Al(OH)3 • HCl + KOH  • HBrO3 + LiOH 

  22. Practice key • Complete and balance the following equations representing neutralization reactions: • 2 CsOH + H2CO3 2H2O + Cs2CO3 • 2 HF + Mg(OH)22H2O +MgF2 • 3HNO3 + Al(OH)33H2O + Al(NO3)3 • = • HCl +KOHH2O +KCl • HBrO3+LiOH H2O + LiBrO3

  23. Which salt is produced when sulfuric acid and calcium hydroxide react? • CaH2 • CaO • CaS • CaSO4

  24. Sulfuric Acid, H2SO4, can be used to neutralize barium hydroxide, Ba(OH)2. What is the formula for the salt produced by this neutralization? • BaS • BaSO2 • BaSO3 • BaSO4

  25. Titration: • A laboratory method for determining the concentration of an unknown acid or base using a neutralization reaction. • A standard solution,(a solution of known concentration), is used.

  26. Equivalence Point • The point at which there are stoichiometrically equivalent amounts of acid and base. • [H+] = [OH-]

  27. Buret Valve

  28. https://www.youtube.com/watch?v=g8jdCWC10vQ Titration Acid with Phenolpthalein End-Point

  29. Indicators • Indicators are chosen, such that they change colors at the range of the pH of interest. • The solution itself at the end-point may be: • Basic, if the reaction involves a strong base and a weak acid. • Neutral, if the reaction involves a strong acid and a strong base. • Acidic, if the reaction involves a strong acid and a weak base.

  30. Methods of Solving Titration Problems: a) using stoichiometry b) using the titration formula MaVa=MbVb. https://www.youtube.com/watch?v=g8jdCWC10vQ

  31. Ex. 1 What is the concentration of HCl if 30.0 mL of 0.10 M NaOH neutralizes 50.0mL HCl?

  32. Ex. 2 A 20.0 mL solution of Sr(OH)2 is neutralized after 25.0 mL of standard 0.05 M HCl is added. What is the concentration of Sr(OH)2?

  33. Ex. 3 • How many mL of 0.20 M H3PO4 are needed to neutralize 55.0 mL of a 0.10 M solution of NaOH?

  34. Ex. 4 • What volume of 0.20M Ca(OH)2 will neutralize 45.0 mL of a 1M solution of HClO3?

  35. Acids with Metals • Acids react with metals, bases do not • It is a single replacement reaction • Metal + acid  hydrogen gas + salt • Example Mg + 2HCl  H2 + MgCl2 • Example Zn + H2 SO4 H2 + ZnSO4

  36. Identify which of the following are neutralization reactions, spontaneous acid + metal reactions (Use table J), or just a plain single replacement or double replacement. • ________________ a) Pb(NO3 )2 + KI  KNO3 + PbI • ________________ b) Zn + CuSO4  ZnSO4 + Cu • ________________ c) Mg + HCl  MgCl + H2 • ________________ d) H2 SO4 + NaOH  Na2 SO4 + H2 • ________________ e) Ag + H3 PO3  AgPO3 + H2 • ________________ f) Ca(OH) + HNO3  H2 O + Ca(NO3 )2 • ________________ g) LiCl + F2  LiF + Cl2 • ________________ h) NHO3 + Mg(OH)2  HOH + Mg(NO3 )2 • ________________ i) H3O+ + OH--  H2O

  37. Acid – Base reactions • Each salt listed in this table can be formed by the reaction between an acid and a base.

More Related