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Acids & Bases.

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Presentation on theme: "Acids & Bases."— Presentation transcript:

1 Acids & Bases

2 Acids Naming Acids Properties of Acids: Sour Taste Electrolytes
Change indicator colors React with metals to form hydrogen React with carbonates to form carbon dioxide React with bases to form salt & water Produces H+ in water Naming Acids Look at ending -ate polyatomic ions -ic acids example: -ite polyatomic ions  -ous acids -ide monatomic ions hydro –ic acid

3 Bases Naming Bases Bitter Feel Slippery Electrolytes
Properties of bases: Bitter Feel Slippery Electrolytes Change indicator colors React with acids to produce salt & water Produce OH- in water Naming Bases name the metal and hydroxide

4 Water Self ionization of water: H2O + H2O  H3O+ + OH-
Hydronium ion H3O+ Hydroxide ion OH- Only 1X 10 –14 M of water molecules do this so [H3O+][OH-] = 1X 10 –14 M If [H3O+]=[OH-] neutral solution If [H3O+]>[OH-] acidic solution If [H3O+]<[OH-] basic or alkaline solution If the hydroxide concentration is 1 X 10–4M, what is the hydronium ion concentration?

5 Formulas [H3O+][OH-] = 1 X 10 –14 M
Use to find one [] given the other [] Find the hydroxide ion concentration if the hydronium ion concentration is 1 X 10-5M. Is this acidic basic or neutral? pH=-log [H3O+] Use to find pH given [H+] Find the pH if the hydronium ion concentration is 2.1 X 10-5M. pOH= -log [OH-] Use to find pOH given [OH-] Find the pOH if the hydroxide ion concentration is 4.1 X 10-5M.

6 pH pH 1-6 7 8-14 Acid neutral base pOH 14-8 7 6-1 pH +pOH=14
Use to find one given the other. Example: Find the pOH if the pH is 8.2. [H+]= 10-pH Use to find [H3O+] given to pH Example: Find the [H+] given a pH of 11.5. [OH-]= 10-pOH Use to find [OH-] given to pOH Example: Find the [OH-] given a pOH of 7.5.

7 pH paper- have indicators on them pH meter
Measuring pH To measure pH: Use acid/base indicators: change color based on [hydrogen ion ], many types pg 590 pH paper- have indicators on them pH meter

8 3 Types of Acids & Bases Arrhenius acids & bases
Bronsted-Lowery acids & bases Lewis acids & bases

9 3 Types of Acids & Bases Arrhenius acid: Produce H+ ion
Arrhenius base: Produce OH- ion Bronsted-Lowery Acid: H+ donor Bronsted Lowery Base: H+ acceptor Lewis acid- can accept pair of e- to form a covalent bond (H+) Lewis base- can donate pair of e- to form a covalent bond (OH-)

10 3 Types of Acids & Bases Type Arrhenius Bronsted-Lowry Lewis Acids
Produce H+ ion H+ donor can accept pair of e- to form a covalent bond (H+) Bases Produce OH- ion H+ acceptor can donate pair of e- to form a covalent bond (OH-)

11 Conjugate Pairs Be able to identify conjugate acid base pair:
Conjugate base – what is left of acid after hydrogen ion is donated Conjugate acid – base plus the hydrogen ion that was donated/accepted Amphoteric- can be acid or base Identify the conjugate acid-base pairs in the following reactions.     H2SO4 + H2O  HSO4- + H3O+     HI(aq) + H2O(l)  H3O+(aq) + I-(aq)

12 ionization Ionization- Strong acid- completely ionizes becomes weak CB
Weak acid- incompletely ionizes becomes strong CB Can write ionization equation: Can write acid dissociation constant (Ka) Ka= [Products]/[Reactants] Don’t include water Smaller #=weaker acid Polyprotic acids- take 1 H at a time Also applies to bases called Kb

13 Example Questions Write the steps in the complete ionization of H2S.
Write the ionization equation and acid ionization constant expression for the following acids. a.       HCl b.      HNO2 c H3PO4 Write ionization equations and base ionization constant expressions for the following bases. a.   propylamine (C3H7NH2) Given: 0.1M solution of ethanoic acid is partially ionized. The [H+] is 1.34 X 10-3M. What is the Ka of ethanoic acid?

14 Neutralization Neutralization- Double displacement reaction NaCl
Acid + Base  salt + water Nitric acid & calcium hydroxide Sulfuric acid & aluminum hydroxide Can find acid & base that form salt NaCl NaHCO3

15 Titration Measure volume of acid soln. Of [unknown] in flask
Titration- Use known to find unknown Need mol ratio for H+:OH- Steps in titration: Measure volume of acid soln. Of [unknown] in flask Add indicator Measured volume of base [known] ‘standard’ are added until slight color change (endpoint) Use MV=MV A 25 mL soln of hydrochloric acid neutralized by 18mL of 1M NaOH. What is the [hydrochloric acid]?

16 Salts Salts Strong acid + strong base neutral salt solution.
Made from an acid & base Strong acid + strong base neutral salt solution. Weak acid + strong base  basic salt solution. Strong acid + weak base  Acidic salt soution. Be able to predict the acid & base that make the salt Buffers- solution where the pH remains constant when an acid/base are added Can absorb or release H+


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