Question

Rezolvati,va rog, exercitiile 4,5,6,9.
*Doresc rezolvarile complete.

Answer 1

4. Co, Z=27 ⇒ 27e⁻ si 27p⁺

ACo=60

N=A-Z=60-27=33

I, Z=53 ⇒ 53e⁻ si 53p⁺

N=137-53=84

P, Z=15 ⇒ 15e⁻ si 15p⁺

N=32-15=17

5. 2,0411u.............................6,022*10^23 atomi
1g.........................................x=2,95*10^23 atomi

6. a) M(NH4)2SO4 = 2(AN+4AH)+AS+4AO= 2(14+4*1)+32+4*16=132g/mol

mN=2*14=28g

mH=4*2=8g

mS=32g

mO=4*16=64g

%N=mN/M(NH4)2SO4*100 = 28/132*100=21,21

%H=mH/M*100=8/132*100=6,06

%S=32/132*100=24,24

%O=64/132*100=48,48

b) MC6H8O6 = 6AC+8AH+6AO=6*12+8*1+6*16=176g/mol

%C=mC/M*100 = 40,91

%H=mH/M*100 = 8/176*100=4,54%

%O = mO/M*100 = 96/176*100 = 54,55

9. MPCl3 = AP+3ACl =31+3*35,5=137,5g/mol

n=m/M=200/137,5=1,45 moli PCl3 

1 mol PCl3...................6,023*10^23 molecule
1,45 moli PCl3.............x=8,76*10^23 molecule

In 137,5g PCl3 se gasesc......................3*35,5=106,5g Cl
Atunci in 200g PCl3.................................xg Cl

x=106,5*200/137,5=154,91g Cl