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Which items do you think are ACIDS & which are BASES?

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Presentation on theme: "Which items do you think are ACIDS & which are BASES?"— Presentation transcript:

1 Which items do you think are ACIDS & which are BASES?
Make a T chart and list the ones you think are acids on one side & the other side label & list the bases

2 NaOH H2O LiOH H3PO3 H3PO4 KOH HCl H2SO4
From the list of compounds, on your T chart continue to list the ones you think are ACIDS under the acid & bases under BASES HCl H2SO4 NaOH H2O H3PO4 KOH LiOH H3PO3

3 Name each of the chemical compounds from the previous slide on your T chart the way you know how, at this time. How do you identify if a compound is an acid when looking at the chemical formula? How do you identify if a compound is a base when looking at the chemical formula?

4 Naming Acids Rule 1: when the name of the anion ends in –ide, the acid name begins with the prefix hydro-. The stem of the anion has the suffix –ic and is followed by the word acid. Ex: HCl – anion is chloride; therefore Hydrochloric acid Practice: H2S Hydrosulfuric acid

5 Naming Acids Rule 2: when the anion name ends in –ite, the acid name is the stem of the anion with the suffix –ous, followed by the word acid. Ex: H2SO3 – anion is sulfite; therefore Sulfurous acid Practice: HClO2 Chlorous acid

6 Naming Acids Rule 3: When the anion name ends in –ate, the acid name is the stem of the anion with the suffix –ic, followed by the word acid. Ex: HNO3 – anion is nitrate; therefore Nitric acid Practice: H2SO4 Sulfuric acid

7 Naming Bases Name bases exactly as you would ionic compounds. Do not add the word base. Ex: NaOH – cation is sodium; anion is hydroxide Sodium Hydroxide

8 Practice Problems #1 Formula Anion Anion name Acid Name 1. HF F- is
fluoride hydrofluoric acid 2. HCl Cl-  is  3. HBr Br-  is  4. H2SO3 SO32- is 5. H2SO4 SO42- is 6. HNO3 NO3- is  7. HNO2 NO2-1 is  8. H2S S2- is  9. H2CO3 CO32- is  10. H3PO4 PO43- is  11. HClO ClO¯ is  12. HClO2 ClO2¯ is  13. HClO3 ClO3¯ is  14. HClO4 ClO4¯ is  15. HIO3 IO3¯ is 

9 Check your neighbors work:
Formula Anion Anion name Acid Name 1. HF F-  is  fluoride hydrofluoric acid 2. HCl Cl-  is  chloride hydrochloric acid 3. HBr Br-  is  bromide hydrobromic acid 4. H2SO3 SO32- is iodide hydriodic acid 5. H2SO4 SO42- is sulfide hydrosulfuric acid 6. HNO3 NO3- is  nitrate nitric acid 7. HNO2 NO2-1 is  acetate acetic acid 8. H2S S2- is  sulfate sulfuric acid 9. H2CO3 CO32- is  carbonate carbonic acid 10. H3PO4 PO43- is  phosphate phosphoric acid 11. HClO ClO¯ is  hypochlorite hypochlorous acid 12. HClO2 ClO2¯ is  chlorite chlorous acid 13. HClO3 ClO3¯ is  chlorate chloric acid 14. HClO4 ClO4¯ is  perchlorate perchloric acid 15. HIO3 IO3¯ is  iodate iodic acid 16. HC2H3O2 NO2¯ is  nitrite nitrous acid

10 Lemons and limes are examples of foods that contain acidic solutions.
5.3 Acids, Bases, and Salts Lemons and limes are examples of foods that contain acidic solutions.

11 Unit 5.3 Outline 5.3.1 Acids and Bases – naming & properties
Reactions of Acids and Bases Salts Electrolytes and Nonelectrolytes Introduction to pH Neutralization Writing Net Ionic Equations

12 Learning Objectives 5.3.1 Acids and Bases
Compare acid & base examples, name acids using naming rules specific for acids Compare the definitions of acids and bases, including Arrhenius, Brønsted-Lowry, and Lewis acids/bases. 5.3.2 Reactions of Acids and Bases Describe the general reactions of acids and bases. 5.3.3 Salts & Naming Acids/Bases Explain how a salt is formed and predict the formula of a salt given an acid and base precursor. Explain how to name acids and bases.

13 Arrhenius Acid: An acid solution contains
Arrhenius Acids Arrhenius Acid: An acid solution contains an excess of H+ ions. Common Properties of Acids 1. Sour taste 2. Turns litmus paper pink 3. Reacts with: Metals to produce H2 gas Bases to yield water and a salt Carbonates to give carbon dioxide

14 Arrhenius Bases: A basic solution contains
an excess of OH– ions. Common Properties of Bases 1. Bitter/caustic taste 2. Turns litmus paper blue 3. Slippery, soapy texture 4. Neutralizes acids

15 Brønsted-Lowry Acids and Bases
A Brønsted-Lowry acid is a proton (H+) donor. A Brønsted-Lowry base is a proton (H+) acceptor. HCl (g) + H2O (l) H3O+ (aq) + Cl- (aq) Acid Base Hydronium ion (hydrated H+) Conjugate Acid/Base Pairs: Two species that differ from each other by the presence of one hydrogen ion. HCO3- (aq) + H2O (l) H2CO3 (aq) + OH- (aq) Acid Base Conjugate conjugate pair 1 conjugate pair 2

16 Brønsted-Lowry Acids and Bases
Identify the base in the following reaction and the compound’s conjugate acid. H2PO4- (aq) + H2O (l) HPO42- (aq) + H3O+ (aq) Base Conjugate Acid a. H2PO4- (aq) b. H2O (l) c. HPO42- (aq) d. H3O+ (aq) a. H2PO4- (aq) b. H2O (l) c. HPO42- (aq) d. H3O+ (aq)

17 Lewis Acid: electron pair acceptor. Lewis Base: electron pair donor.
Lewis Acid-Bases Lewis Acid: electron pair acceptor. Lewis Base: electron pair donor.

18 Summary of the Acid/Base Theories
The theory that best explains the reaction of interest is used.

19 Reactions of Acids 1. Reactivity with Metals
Acids react with any metals above hydrogen in the activity series. 2 HCl (aq) + Mg (s) MgCl2 (s) + H2 (g) In general: acid + metal salt + hydrogen 2. Reactivity with Bases Also called a neutralization reaction. 2 HCl (aq) + Ca(OH)2 (aq) CaCl2 (aq) + 2 H2O (l) In general: acid + base salt + water

20 Reactions of Acids 3. Reactivity with Metal Oxides
2 HCl (aq) + Na2O (s) NaCl (aq) + H2O (l) In general: acid + metal oxide salt + water (base) 4. Reactivity with Metal Carbonates 2 HCl (aq) + Na2CO3 (aq) NaCl (aq) + H2O (l) + CO2 (g) In general: acid + carbonate salt + water + carbon dioxide (base)

21 Base Reactions Bases can be amphoteric
(act as either Brönsted acids or bases) As a base: Zn(OH)2 (aq) + 2 HBr (aq) ZnBr2 (aq) + 2 H2O (l) As an acid: Zn(OH)2 (aq) + 2 NaOH (aq) Na2Zn(OH)4 (aq) NaOH and KOH can also react with metals. 2 NaOH (aq) + 2 Al (s) + 6 H2O (l) 2 NaAl(OH)4 (aq) + 3 H2 (g) In general: base + metal + water salt + hydrogen

22 Salts Salts: products from acid-base reactions.
HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l) Sodium chloride (table salt) Salts are ionic compounds. Salts contain a cation (a metal or ammonium ion) derived from the base and an anion (excluding oxide or hydroxide ions) derived from the acid. Salts are generally crystalline compounds with high melting and boiling points.

23 Salts Practice Which salt forms in the reaction of
aluminum oxide and hydrobromic acid? Al2O3 (s) + 6 HBr (aq) AlBr3 (aq) + 3 H2O (l) a. AlBr b. AlBr3 c. Al2Br d. Al2Br3

24 Learning Objectives 5.3.4 Electrolytes and Nonelectrolytes
Describe properties, ionization, dissociation, and strength of electrolytes and compare them to nonelectrolytes. 5.3.5 Introduction to pH Calculate the pH of a solution from the hydrogen ion concentration. 5.3.6 Neutralization Describe a neutralization reaction and do calculations involving titrations.

25 Electrolytes and Nonelectrolytes
Electrolytes: compounds that conduct electricity when dissolved in water. Nonelectrolytes: substances that do not conduct electricity when dissolved in water. Comparing Solution Conductivity (Distilled water) (Sugar solution) (Salt solution)

26 Electrolytes and Nonelectrolytes
Ion movement causes conduction of electricity in water. 3 classes of compounds, acids, bases, and salts are electrolytes because they produce ions in water when they dissolve.

27 Electrolytes and Nonelectrolytes Practice
Which compound will not dissociate in water? a. HCl b. KBr c. NaOH d. CH3OH a. HCl (acid, dissociates) b. KBr (salt, dissociates) c. NaOH (base, dissociates) d. CH3OH (organic, does not dissociate)

28 Dissociation of Electrolytes
Salts dissociate into their respective cations and anions when dissolved in water. NaCl (s) Na+ (aq) + Cl- (aq) Hydrated sodium (purple) and chloride (green) ions The negative end of the water dipole is attracted to the positive Na+ ion. When NaCl dissolves in water, each ion is surrounded by several water molecules. The permanent dipoles in the water molecules cause specific alignment around the ions.

29 Electrolyte Ionization
Ionization: process of ion formation in solution. Ionization results from the chemical reaction between a compound and water. Acids ionize in water, producing the hydronium ion (H3O+) and a counter anion. HCl (g) + H2O (l) H3O+ (aq) + Cl- (aq) H3PO4 (aq) + H2O (l) H2PO4- (aq) + H3O+ (aq) Bases ionize in water, producing the hydroxide ion (OH-) and a counter cation. NH3 (aq) + H2O (l) OH- (aq) + NH4+ (aq)

30 Strong and Weak Electrolytes
Strong electrolytes: undergo complete ionization in water. Example: HCl (strong acid) Weak electrolytes: undergo incomplete ionization in water. Example: CH3COOH (weak acid) HCl (left) is 100% ionized. CH3COOH exists primarily in the unionized form.

31 Strong and Weak Electrolytes
Double arrows indicate incomplete ionization (typically weak electrolytes). HF (aq) + H2O (l) F- (aq) + H3O+ (aq)

32 Salts Salts can dissociate into more than 2 ions,
depending upon the compound. A 1 M solution of NaCl produces a total of 2 M of ions. NaCl (s) Na+ (aq) + Cl- (aq) 1M 1M 1M A 1 M solution of CaCl2 produces a total of 3 M of ions. CaCl2 (s) Ca2+ (aq) + 2 Cl- (aq) 1M 1M 2M

33 Salts Practice What is the concentration of bromide ion in a
1.5 M solution of magnesium bromide? a. 0.75M b. 1.5M c. 3.0M d. 4.5M For every one mole of MgBr2, 2 moles of Br- ionize. MgBr2 (s) Mg2+ (aq) Br- (aq) 1.5 M 1.5M 3.0M

34 Autoionization of Water
Pure water auto(self) ionizes according to the reaction: H2O (l) + H2O (l) H3O+ (aq) + OH– (aq) Based on the reaction stoichiometry: Concentration H3O+ = Concentration OH– = 1 x 10–7 M [H3O+] x [OH–] = (1 x 10–7)2 = 1 x 10–14 When acid or base is present in water, [H3O+] and [OH-] change. In acidic solutions, [H3O+] > [OH–]. In basic solutions, [H3O+] < [OH–].

35 In pure water, [H3O+] = 1 x 10-7 M, so
Introduction to pH pH = - log[H3O+] In pure water, [H3O+] = 1 x 10-7 M, so pH = - log(1 x 10-7) = 7 Neutral High H3O+ Low OH- Increasing acidity Increasing basicity Low H3O+ High OH- The pH scale

36 pH

37 pH Practice By what factor is a solution of pH = 3 more acidic
than a solution with a pH = 5? a. 2 b. 20 c. 200 d. 100 pH = 5 means [H3O+] = 1 x 10-5 M pH = 3 means [H3O+] = 1 x 10-3 M 1 x 10-3 M Factor = = 100 1 x 10-5 M

38 pH Calculations pH = - log[H3O+] [H3O+] = 10-pH Generalizations
Exponent = pH pH = 5 [H3O+] = 1 x 10-5 M The pH is between the exponent and next lowest whole number pH = 4.7 If exactly 1 [H3O+] = 2 x 10-5 M If a number between 1 and 10

39 pH Calculations Calculate the pH of a 0.015 M [H3O+] solution.
pH = - log(0.015) = 1.8 The number of decimal places for the answer must equal the number of significant figures in the original number.

40 pH Calculations Practice
What is the pH of a M HCl solution? a b. -2.0 c. 1.70 d. 1.7 pH = - log(0.020) = 1.7

41 What is the pH of a NaOH solution with a
pH Calculations Practice What is the pH of a NaOH solution with a [OH-] = 2.5 x M? a. 3.4 b. 10.6 c. -3.4 d pOH = - log [OH-] pOH = - log (2.5 x 10-11) = 10.6 pH + pOH = 14 pH = 14 – 10.6 = 3.4

42 Neutralization General Reaction acid + base salt + water Example
HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l) Overall Ionic Equation: H+(aq) + Cl- (aq) + Na+ (aq) + OH- (aq) Na+ (aq) + Cl- (aq) + H2O (l) All species are included; soluble compounds shown as ions. Net Ionic Equation: H+ (aq) + OH- (aq) H2O (l) Spectator ions (green) are removed from both sides.

43 Titration Titration: experiment where the volume of one reagent
(titrant) required to react with a measured amount of another reagent is measured. Titrations allow the amount of an acid or base present in a sample to be determined. Indicators are used to signal the endpoint of a titration, the point when enough titrant is added to react with the acid/base present. Burets deliver measured amounts of the titrant into a solution of the unknown reagent. Endpoint

44 Titration Calculations
If mL of M HCl is used to titrate mL of NaOH, what is the molarity of the base? Reaction HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l) Knowns mL of M HCl 25.00 mL NaOH Solving for Molarity of base Calculate mol HCl 1000 mL soln 1 mol NaOH 22.59 mL × × = mol NaOH 1 mol HCl mol NaOH L soln Molarity NaOH = = M NaOH

45 Titration Calculations
What is the molarity of a NaOH solution if mL of base is required to titrate g of oxalic acid (H2C2O4)? Reaction H2C2O4 (aq) + 2 NaOH (aq) NaC2O4 (aq) + 2 H2O (l) Knowns g H2C2O4 21.93 mL NaOH Solving for Molarity of base Calculate 1 mol H2C2O4 90.04 g H2C2O4 2 mol NaOH 0.243 g H2C2O4 × × = mol NaOH 1 mol H2C2O4 mol NaOH L soln Molarity NaOH = = M NaOH Always check reaction stoichiometry!

46 Titration Calculations Practice
What is the concentration of a nitric acid solution if 10.0 mL of the solution is neutralized by 3.6 mL of 0.20 M NaOH? Reaction a M b M c M d. 5.6 M HNO3(aq)+NaOH(aq) NaNO3(aq)+ H2O(l) Knowns mL, 0.20 M NaOH 10.00 mL HNO3 Solving for Molarity of acid Calculate 0.20 mol NaOH 1000 mL NaOH 1 mol HNO3 3.60 mL NaOH × × = mol HNO3 1 mol NaOH mol HNO3 L soln Molarity HNO3 = = M HNO3

47 Learning Objectives 5.3.7 Writing Net Ionic Equations
Write net ionic equations using the stated rules.

48 Rules for Writing Net Ionic Equations
1. Strong electrolytes are written as the corresponding ions. Example: NaOH (aq) is written as Na+(aq) + OH-(aq) 2. Weak electrolytes and nonelectrolytes are written as molecules. Example: CH3OH(aq), CH3COOH(aq), etc. 3. Solids and gases are written as their molecular forms. 4. The net ionic equation does not include spectator ions. 5. The net ionic equation must balance atoms and charge.

49 Net Ionic Equations Practice
Write the net ionic equation (NIE) for the following reaction: BaCl2 (aq) + Na2SO4 (aq) BaSO4 (s) + 2 NaCl (aq) Total Ionic Equation Ba2+ (aq) + 2 Cl- (aq) + 2 Na+ (aq) + SO42- (aq) BaSO4 (s) + 2 Na+ (aq) + 2 Cl- (aq) Spectator Ions Net Ionic Equation Ba2+ (aq) + SO42- (aq) BaSO4 (s)

50 Net Ionic Equations Practice
Write the net ionic equation (NIE) for the following reaction: Na2CO3 (aq) + 2 HCl (aq) CO2 (g) + 2 NaCl (aq) + H2O (l) Total Ionic Equation 2 Na+ (aq) + CO32- (aq) + 2 H+ (aq) + 2 Cl- (aq) 2 Na+ (aq) + 2 Cl- (aq) + CO2 (g) + H2O (l) Spectator Ions Net Ionic Equation 2 H+ (aq) + CO32- (aq) CO2 (g) + H2O (l)

51 Net Ionic Equations Practice
What is the net ionic equation when hydrobromic acid reacts with potassium hydroxide? a. b. c. d. H+ (aq) + Br- (aq) HBr (l) K+ (aq) + OH- (aq) KOH (s) K+ (aq) + H- (aq) KH (s) H+ (aq) + OH- (aq) H2O (l) Equation HBr (aq) + KOH (aq) KBr (aq) + H2O (l) Total Ionic Equation H+(aq)+Br-(aq)+K+(aq)+OH-(aq) K+(aq)+Br-(aq)+H2O(l)


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