Question

2 si 6 va rog. Dau coroana

Answer 1

2.

+2      0         0     +1

NiO + H2 --> Ni + H2O

Ni⁺²_+2e-__> Ni⁰ reducere (ag ox) NiO

H2⁰_-2e-__> H2⁺ ox (ag. red) H2

+2       0       0     +2

CuO + C --> Cu + CO

Cu⁺²_+2e-__> Cu⁰ red. (ag. ox) CuO

C⁰_-2e-__> C⁺² ox (ag. red) C

+5         0       +3           0

V2O5 + Al --> Al2O3 + V

 6x   V2⁺⁵_+10e-__> 2V⁰ red (ag. ox) V2O5

10x   2Al⁰_-6e-__> Al2⁺³ ox (ag red) Al

=>

3V2O5 + 10Al --> 5Al2O3 + 6V

6.

a)

  +5            -1         -1                0

KClO3 + HCl --> KCl + H2O + Cl2

1x   Cl⁺⁵_+6e-__> Cl⁻ red (ag ox) KClO3

3x  2Cl⁻¹_-2e-_> Cl2⁰ ox. (ag red) HCl

=> prin oxidarea HCl

b)

KClO3 + 6HCl --> KCl + 3H2O + 3Cl2

c)

100% KClO3.......................... 2,5 impur

98% ....................................... a = 2,25 pur

  2,25 g                                     n moli

KClO3 + 6HCl --> KCl + 3H2O + 3Cl2

122,5                                             3

=> n = 2,25x3/122,5 = 0,055 moli Cl2

d)

2,25 g    md g

KClO3 + 6HCl --> KCl + 3H2O + 3Cl2

122,5      6x36,5

=> md = 2,25x6x36,5/122,5

= 4,02 g HCl

stim ca c% = mdx100/ms

=> ms = mdx100/c%

= 4,02x100/36 = 11,17 g sol HCl

stim ca ro = ms/Vs

=> Vs = ms/ro

= 11,17/1,183 = 9,45 cm3 sol. HCl