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ACIDS AND BASES

ACIDS AND BASES. Acids found around the house. Citric - all citrus fruit Acetic acid – vinegar Carbonic – soda Tannic – tea Lactic- milk, yogurt Sulfuric – car battery Hydrochloric – metal and masonry cleaning. Organic acids are those made by an organism

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ACIDS AND BASES

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  1. ACIDS AND BASES

  2. Acids found around the house • Citric - all citrus fruit • Acetic acid – vinegar • Carbonic – soda • Tannic – tea • Lactic- milk, yogurt • Sulfuric – car battery • Hydrochloric – metal and masonry cleaning

  3. Organic acids are those made by an organism • Mineral acids or inorganic are those that can be made directly at the lab bench, also referred to as industrial acids.

  4. 3 Common Industrial Acid • Sulfuric ( H2SO4 ) used in most manufacturing Conc 98 % , specific gravity 1.84g/ml dilute = 1 part acid to 5 parts water 2. Hydrochloric (HCl ) masonry and metal cleaning . Conc 36 % , specific gravity 1.19 g/ml dilute = 1 part acid to 4 parts water.

  5. 3 Nitric acid ( HNO3 ) Tanning leather, making fertilizer and explosives Conc 70 % Specific gravity 1.42 g/ml dilute = 1 part acid to 3 parts water Demo the three.

  6. Have a sour taste Affect indicators blue litmus turns red Acids neutralize bases to make a salt + water Are electrolytes Many React with metals to release hydrogen Have a bitter taste Affect indicators red litmus turns blue B-B base = blue Bases neutralize acids to make a salt + water Are electrolytes Feel slippery Acids Bases

  7. Common bases around the house • Milk of magnesa Mg(OH)2 • Draino NaOH • House hold Ammonia NH4OH • Rolaids Mg(OH)2 / CaCO3 • Tums Al(OH)3 ? • Milanta , peptobismo • Lime CaO for the lawn. Plus H2O makes Ca(OH)2

  8. Arrhenius’s Theory of ionization H+ • H2O + H2O → H3O+ + OH- • Water + water yields Hydronium ion + hydroxide ion • If H2O loses an H+ what do you have left? an OH- ion

  9. You get 1.0 x 10-7 H3O+ and 1.0 X 10-7 OH- for every liter of pure water. • Notice that the hydronium and hydroxide ion concentrations are equal, that’s a neutral solution. • When H3O+ > OH- its an acid • When OH- > H3O+ it’s a base

  10. The pH scale is a system to express the “ power of hydronium” . The pH of a neutral solution is 7 The H3O+ concentration is 1.0 X 10 -7 When pH is 3, [H3O+ ] = 1.0 x 10 -3 When pH is 9 [H3O+ ] is 1.0 x 10 -9 [ ] means concentration in moles/liter is

  11. This true so long as the conc is 1.0 times the exponent. • If its not, its math time. • pH = -log( H3O+ ) • What is the pH when[ H3O+ ] is 3.4 x 10-5 ? • - log 3.4 2nd ee - 5 ) enter • You get 4.468521 or 4.47 as the pH

  12. Other direction • pH = 4.47 what is the [H3O+] ? • Antilog ( -ph ) = [ H3O+ ] • 2nd log - 4.47 ) enter • You get 3.4 x 10-5

  13. Back to Arrhenius • In a neutral solution [ H3O+ ] = [ OH- ] • Because both equal 1.0 x 10-7 • [ H3O+ ] X [ OH- ] = 1.0 x 10-14 • Which is a constant, so given either the [H3O+] or the [OH- ] you can solve for the other.

  14. [ H3O+ ] = 1.0 x 10-14 [ OH- ] [ OH- ] = 1.0 x 10-14 [ H3O+ ]

  15. Bronsted and Lowery Defined an acid as a proton donor and a base as a proton accepter. There for any substance that contains ionizable hydrogen is an acid. And an negative ion can be a base.

  16. HCl + H2O → H3O+ + Cl- in the forward reaction the HCl is the acid and the water is the base. Short form HCl → H+ + Cl- it is assumed you know the water is required.

  17. Conjugate acid base pairs A conjugate base is a base that is produced when an acid gives up a proton. H2SO4 → HSO4- + H+ In this case the HSO4- is the base produced when the H2SO4 gave up the H+ because the bisulfate ion has a negative charge it is a base according to Bronsted/Lowery

  18. The only difference between a conjugate acid and its conjugate base is one stinking hydrogen. The acid has it the base does not. So to determine the conjugate base all you do is subtract one H from the acid and make the resulting ion (-)

  19. Monoprotic acids only have one ionizable Hydrogen , HCl, HNO3, H C2H3O2 Diprotic acids have two ionizable hydrogens H2SO4 and H2CO3 Triprotic acids have three. H3PO4

  20. Amphprotic substances are those that can act as either an acid or a base. The HSO4- ion has an ionizable Hydrogen and a negative charge. So it can give up the H to act as an acid or since its negative it can accept an H to act as a base. These substances are commonly called Buffers. Why?

  21. Titration • Acid buret Base buret The Process of reacting a solution of known concentration with one of unknown concentration to determine The concentration of the unknown solution.

  22. Work in progressnot done yet

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