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Acid/Base.

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Presentation on theme: "Acid/Base."— Presentation transcript:

1 Acid/Base

2 Acids pH under 7 Sour react w/ metals to form H2
Turns litmus paper Red Electrolyte Combines with a base to form water and salt

3 Common acids and naming
Most acids start with hydrogen, H or H+ combined with an anion Common Acids: Hcl, H2so4, h3po4, h2co3, Hno3 Naming…. Anion ends in “ide” = hydro____ic acid….. So Hcl = hydrochloric acid Anion ends in “ate” = _______ic acid…. so HNO3 = Nitric acid Anion ends in “ite” = _______ous acid…. So Hno2 = nitrous acid

4 Bases Ph over 7 Bitter, slippery Turns litmus paper Blue Electrolyte
Combines with an acid to form water and salt

5 Common Bases and Naming
Common Bases: Naoh, koH, Mg(Oh)2, Ca(Oh)2, al(oh)3 Most bases start with a metal and end in a oh- anion Name the metal, ends in hydroxide Exception: Nh3 = ammonia

6 Strong acids vs. weak acids
Strong acids ionize easily in solution Ex: HCL  H+ + cl- , ph = 2-3 ; The Hydrogen ion and the chloride ion can bond with other chemicals in the air, on your skin, in solutions, etc. making more dangerous than weak acids. Weak acids do not ionize easily in solution Ex: hC2h3o2   H+ + C2h3o2- , ph = 2-3 ; vinegar will not ionize as readily as a strong acid, it will go back and forth from reactant to product.

7 Ph scale acid Base = neutral ph is measured by indicators ( usually weak acids or bases sensitive to ph), ph meter or probe Ph scale is based on concentration of the h+ ion Ph = the power of hydrogen

8 Ph The concentration of the h+ ion, [h+] , will increase or decrease ten X for each unit on the scale. Acids: a ph of 2 has a [h+] 10 x more than that of a ph of 3 and 100 x more than that of an acid with a ph of 4. Bases: ph of 10 has a [h+] 10 x less than a ph of 9 and 100x less than that of a base with a ph of 8.

9 Ph is a logarithmic scale
[h+] = concentration of the hydrogen ion (M) is the unit that represents concentration) Ph = - log [h+] ; [h+] = 10 -ph [oh-] = concentration of the hydroxide ion (M) Poh = - log [oh-] ; [oh-] = 10 -poh Ph + poh = 14 [h+] x [oh-] = 1 x Ph scale focuses on hydrogen to determine acid/base

10 Log function and ph [h+] = 1 x 10 -3 then ph=3 and poh = 11
[oh-] = 1 x then poh = 14 and ph = 0 [oh-] = 1 x then poh = 8 and ph = 6 [oh-] = 1 x 10-4 then poh =4 and ph = 10

11 Sample problem #1 A. [h+] is 1 x M, what is the ph?, what is the poh, is this acidic or basic? B. [oh-] is 1 x M, what is the poh? What is the ph? Is this acidic or basic C. how many times or how much [h+] does B. have compared to a.? Which one is more acidic?

12 Answer #1 A. Ph = 13, poh = 1, basic B. Poh = 10, ph = 4, acidic
C. a ph of 4 has 109 x more hydrogen concentration, [h+], than a ph of 13 B is more acidic

13 Sample problem #2 A. How much more acidic, [h+], is a ph of 3 compared to a ph of 5? B. how much more basic, [oh-] , is a ph of 10 than a ph of 1?

14 Answer #2 A. A ph of 3 is 100 x more acidic or has 100 x more [h+] than a ph of 5 B. a ph of 10 is 109 x more basic or has 109 x less [H+] than a ph of 1

15 Sample Problem #3 Given [h+] = 2.3 x M, calculate the ph. Poh and [oh-]?

16 Answer #3 Ph = - log (2.3 x 10 -13) = 12.64 Poh = 1.36 ; ph + poh = 14
10 –Poh = [oh-] = 4.4 x 10-2 = 0.044M

17 Sample problem #4 A. given [h+] = 2.3 x M , calculate ph, poh, and [oh-] . B. given poh = 11.5, calculate the ph, [oh-] and the [h+] . C. given [oh-] = 3.6 x 10-3 M, calculate the poh, ph and [h+].

18 Answer #4 A. ph = -log (2.3 x 10 -3) = 2.64 Poh = 11.36
[oh-] = = 4.3 x M

19 Answer #4 B. ph = 2.5 [h+] = 10 -2.5 = 3.16 x 10 -3 M
[oh-] = = 3.16 x M

20 Answer #4 C. poh = -log (3.6 x 10 -3 ) = 2.44 Ph = 11.56
[h+] = = 2.7 x M


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