Question

Va rog sa ma ajutati!

Answer 1

1.

stim ca pH = -lg[H3O+]

si pOH = -lg[HO-]

intre pH si pOH avem relatia

pH + pOH = 14

a. pH = -lg[10-12] = 12

=> pOH = 14-12 = 2

b. pOH = -lg[10-5] = 5

=> pH = 14-5 = 9

c. pH = -lg[10-2] = 2

=> pOH = 14-2 = 12

d. pH = -lg[10-72] = 7

pOH = 14-7 = 7

e. pOH = -lg[10-4] = 4

=> pH = 14-4 = 10

f. pOH = -lg[10-11] = 11

=> pH = 14-11 = 3

2.

[H3O+] = 10la-pH

[HO-] = 10la-pOH

a. [H3O+] = 10la-7 mol/L

pOH = 14-7 = 7

=> [HO-] = 10la-7 mol/L

b. [HO-] = 10la-3 mol/L

pH = 14-3 = 11

=> [H3O+] = 10la-11 mol/L

c. [H3O+] = 10la-6 mol/L

pOH = 14-6 = 8

=> [HO-] = 10la-8 mol/L

d. [HO-] = 10la-12 mol/L

pH = 14-12 = 2

=> [H3O+] = 10la-2 mol/L

3.

a)

stim Cm = roxc%x10/miu, miuHCl = 36,5 g/mol

=> Cm = 1,15x0,3x10/36,5 = 0,1 mol/L (rotunjit)

HCl = acid tare => [H3O+] = Cm => pH = -lgCm

= -lg10-1 = 1

=> pOH = 14- 1 = 13

b)

stim Cm = roxc%x10/miu, miuNaOH = 40 g/mol

=> Cm = 1,02x0,0392x10/40 = 0,01 mol/L (rotunjit)

NaOH = baza tare => [HO-] = Cm => pOH = -lgCm

= -lg10-2 = 2

=> pH = 14-2 = 12