A Lista de Exercícios Analítica

1. Monte a cueva de titulacão de 25.0 mL de H3PO4 0, 10 mol L 'com NaOH 0,10 mal - calculando os requintes pontos :

a) 0,0 mL Kan= 7,5x10-3 Kaa = 6,2x10-8 Kaz= 1,0 x 10-12

H3PO4 -

H+ + Hapou

7, 5810-3 = x2

0,10-X x2 + 7,5*10-3X - 7,5x10 "=0

X-7,5x10*3!/3,05625 x103

A = ( 17,5 * 10 - 3) at 4. (- 9,5*10-4) A = 5.625 x 10-5 + 3x10-3 4 = 3,05625x10

x = - 7,5 x 10-3 ± 0,055 = -7,5x10 -3 +0.055

x=0,0238

molt

pH= 1,6

b) 10,0 mL

n mols H3PO4 i = 0,10 0,025 = 2, 5 x 10-3 mol n mobs Nao lade = 0,10 0,01 = 1 x 10-3 mol n mals H 3 PO 4 rest - 2,5x10 -3 -1.0x10 3 = 1, 5 x 10-3 mob.

7,5x10 3 = x. 1.0x10 - 3

1,5X10-3 x = 0,0 1 1 25 no hi

pH = 1,95

c) 25,0 mL (10 PE)

25.0.0,10 = 0,05 molt -

Kai Kw = 7,5 x 10-17

<

Kai kas [Sal] = 2, 3 25 x 10-11

= 12,325 x 10-11

-14 1 X 10-10

1 H+1=1 (7.5 x 10-3). (6.2 x 10-8).0,05

V (7,5 x 10-3) + 0,05

0,0575

(4+1 = 2x 10-3 mat

pH= 4,7

d) 50.0 mL (QOPE?

25,0 0,10 -0,033 mall

45.00

pH + pot = 14 PHE 14-4, 1. pH = 9,9

Kn= 1,62x10 -7 = x2

0.039 - X x2 = 5,313 x 10 9 X = 7,3 x 10-5 mall-= 104]

e) 62.5 mL

OH = 0,1 162,5-2.25) = 0,0 14 0 moll