Question

determinati raportul atomic reprezentat dee masa si componenta procentuala pentru : a) sulfura de aluminiu
b) hidroxid de znc
c) carbonat de aluminiu

Answer 1

Al2S3

raport atomic=r.a. =2Al:3S=2:3

raport de masa =r. m. =2A Al :3 A S =2.27:3.32=54:96=9:16
                                                                           ( se simplifica cu 6)

Compozitia procentuala prin masa moleculara

MAl2S3=2.27+3.32=150

150 g Al2S3---------54 gAl--------96 g S
100 g Al2S3----------X---------------Y
X=100.54:150=36 la suta Al
y=100.96:150=64 la suta S


Zn( OH)2

r.a.=1Zn:2O :2H=1:2:2

r.m. =AZn:2AO:2AH=65 :2.16 :2=65:32:2

Comp.procentuala

MZn(OH)2 =65+32+2=99

99g Zn(OH)2-------65gZn-------32gO-------2gH
100gZn(OH)2---------x--------------y-----------z
x=100.65:99=65,65 la suta Zn
y=100.32:99=32,32 la suta O
Z=100.2:99=2,02 la suta H



Al2( CO3)3

r.a. =2Al :3C :9O=2:3:9
r.m.=2A Al :3A C :9A O =2.27 :3.12 :9.16=54:36:144=9:6:24 =3:2:8
                                                                 (Se simpl.cu 6 ,apoi cu 3)


Comp.proc. prin masa moleculara

MAl2 (CO3)3 =2.27+3.12+9.16=54+36+144=234

234g Al2(CO3)3 --------54 g Al-------36 g C-----144 g O
100 g--------------------------x------------y-----------------z

x=100.54:234=23,07 la suta Al
y=100.36:234=15,38 la suta C
z=100.144:234=61,53 la suta O