Unit 10 acids and bases
This presentation is the property of its rightful owner.
Sponsored Links
1 / 23

Unit 10- Acids and Bases PowerPoint PPT Presentation


  • 73 Views
  • Uploaded on
  • Presentation posted in: General

Unit 10- Acids and Bases. Acidity Alkalinity Arrhenius acid Arrhenius base Bronsted-Lowry acid Bronsted-Lowry base Buffer Electrolyte. Hydrogen ion Hydronium ion Indicator Neutralization pH scale Salt Titration. Properties of Acids. Have sour taste

Download Presentation

Unit 10- Acids and 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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Unit 10 acids and bases

Unit 10- Acids and Bases

  • Acidity

  • Alkalinity

  • Arrhenius acid

  • Arrhenius base

  • Bronsted-Lowry acid

  • Bronsted-Lowry base

  • Buffer

  • Electrolyte

  • Hydrogen ion

  • Hydronium ion

  • Indicator

  • Neutralization

  • pH scale

  • Salt

  • Titration


Properties of acids

Properties of Acids

  • Have sour taste

    • ***take my word, don’t taste lab chemicals

  • Can conduct electric current in solution

    • Electrolytes

    • Good conductor= strong acid

    • Poor conductor= weak acid

  • Turns blue litmus paper red “blue to red a-cid”

  • Most common acids are liquid or gas

  • React with metals to produce H2 gas

    • Above H2 in Table J will react (single-replacement)

  • React with bases to form salt and water

    • Neutralization (double-replacement

  • Can generate hydronium ions H3O+ in water

  • pH less than 7


Acids

Acids

  • Sulfuric- car batteries

  • Ascorbic- tomatoes


Properties of bases

Properties of Bases

  • Have bitter taste

    • ***take my word, don’t taste lab chemicals

  • Can conduct electric current in solution

    • Electrolytes

    • Good conductor= strong base

    • Poor conductor= weak base

  • Most common bases are solid

  • React with acids to form salt and water

    • Neutralization (double-replacement

  • Can generate hydroxide ions OH- in water

  • Turns red litmus paper blue “blue base”

  • pH greater than 7


Bases

Bases

  • Sodium bicarbonate


Acid and base strength

Acid and Base Strength

  • Due to degree of ionization

  • Complete dissociation-strong acid or base


Definitions of acids and bases

Definitions of Acids and Bases

  • Arrhenius Theory-

    • Arrhenius acid- produces H+ or H3O+ as the only positive ions in solution

      • Hydrogen ions will attract to water molecule and form hydronium ions

    • Arrhenius base- produces OH- ions in solution

      • Except!!! Not all bases have OH- ions

  • Drawbacks:

    • Limited to aqueous solutions

    • Can’t classify amphoteric substances (substances that act as bases and acids)


Unit 10 acids and bases

Arrhenius acid is a substance that produces H+ (H3O+) in water

Arrhenius base is a substance that produces OH- in water


Definitions of acids and bases con t

A Brønsted-Lowry acid is a proton donor

A Brønsted-Lowry base is a proton acceptor

Definitions of Acids and Bases con’t

  • BrØnsted-LowryTheory-

    • B-L acid- proton donor

    • B-L base- proton acceptor

    • Proton = hydrogen ion that has lost its electron

conjugateacid

conjugatebase

acid

base


Definitions of acids and bases con t1

Definitions of Acids and Bases con’t

  • All Arrhenius acids are also B-L acids

  • B-L bases expand the substances that can be considered bases


Naming acids

Naming acids

  • If an acid molecule forms 1 H ion it’s a:

    • Monoprotic acid (HCl)

  • If an acid molecule forms 2 H ions it’s a:

    • Diprotic acid (H2SO4)

  • If an acid molecule forms 3 H ions it’s a:

    • Triprotic acid (H3PO4)


Naming acids con t

Naming acids con’t

  • For binary acids:

    • Hydro + element name – ine + ic + acid

    • Ex: HCl- hydrochloric acid

    • Try HF- _________________________

  • For ternary acids:containing H, O and another element

    • 3rd element name, modify to end in –ic or –ous + acid

    • Ex: HNO3- nitric acid nitrogen –ogen + ic + acid

    • Try HNO2- _____________________


Naming bases

Naming bases

No oxygen 

  • Name of positive ion + hydroxide

    • Ex: Ba(OH)2- barium hydroxide

    • Try KOH- ____________________

More oxygen 

Less oxygen 


Reactions with acids and bases

Reactions with acids and bases

  • Acids and metals-

    • Use Table J in Ref Tables

    • Acid will react with anything above H2

    • Single replacement rx’s

      Zn(s) + 2HCl(aq)  H2(g) + ZnCl2(aq)

  • Neutralization reactions-

    • Arrhenius acid + Arrhenius base  salt + water

    • Equivalence pt- pt at which neutralization is complete; when H30+ ion = OH- ions


Neutralization rx

Neutralization Rx

  • Words:

    Hydrochloric acid + sodium hydroxide  water + sodium chloride

  • Chemical formulas:

    HCl(aq) + NaOH(aq)  H2O(l) + NaCl(aq)

  • Ions:

    H+(aq) + Cl-(aq) + Na+(aq) + OH-(aq)  H2O(l) + Na+(aq) + Cl-(aq)

  • Omitting spectator ions:

    H+(aq) + OH-(aq)  H2O(l) or

    H3O+(aq)+ OH-(aq)  2H2O(l)


Neutralization rx s con t

Neutralization Rx’s con’t

  • Diprotic acid + dihydroxy base makes 2 water molecules

    • Ex: Ca(OH)2 + H2SO4 2H2O + CaSO4

  • Acids and bases with unequal H+ and OH- needs to be balanced

    • Ex: ___Mg(OH)2 + __HCl  __H2O + ___MgCl2

      (two) (one)

  • Salts produced- ionic substance with a metal and nonmetal or polyatomic ion


Titrations

Titrations

  • Process of adding a measured volume of an acid or base of known concentration to an acid or base of unknown concentration until neutralization occurs

  • Cacid x Vacid = Cbase x Vbase

    (known) (known) = (unknown) (known)

    molarity x volume = molarity x volume

  • Standard solution= soln of known concentration

  • There needs to be a 1:1 ratio of H+ to OH-

    • Diprotic ex: 2.5M H2SO4 = 5M H+

    • Triprotic ex: 2MH3PO4 = 6M H+

    • Dihydroxy base ex: .5MBa(OH)2 = 1M OH-


Acidity and alkalinity of solutions

Acidity and Alkalinity of Solutions

  • Relative strength of an acid or base in terms of their H+ or OH- concentrations

  • H2O  H+ + OH-

    • Le Chateliers principle [H+] = [OH-]

    • If one increases the other decreases

      • If you add HCl to water H+ increases so it becomes more acidic


Ph scale

pH scale

  • Expresses the strength of acids and bases

  • Instead of using very small numbers, we just use the NEGATIVE power of 10 on the Molarity of the H+ (or OH-) ion.

  • pH change of 1 is a 10 fold increase or decrease in ions


Ph indicators

pH indicators

  • Substance that changes its color when it gains or loses a proton (H+ ion)

  • Universal indicators are a mix of a few indicators

  • pH meter- electric instrument with probes sensitive to H3O+ creates voltage between probes


Buffers

Buffers

  • Solutions that resist change in pH

  • Weak acid or base

  • Usually a weak acid and its conjugate base

  • Stabilizes pH

    • Foods, shampoo, antacids, blood


  • Login