pag. 68. Chenar 1:
a) MSO₂ = 64g/mol
raport de masa ⇒ S:O = 32:32 = 1:1
b) MMgO = 40g/mol
raport de masa ⇒ Mg:O = 24:16 = 3:2
c) MP₂O₅ = 142g/mol
raport de masa ⇒ P:O = 62:80 = 31:40
d) MH₂SO₄ = 98g/mol
raport de masa ⇒ H:S:O = 2:32:64 = 1:16:32
pag. 68. Chenar 2:
a) MSO₂ = AS + 2AO = 32+2×16 = 64g/mol
raport de masa ⇒ S:O = 32:32 = 1:1
2 parti masice........1 p.m S............2 p.m O
100 p.m................x........................y
x = 100/2 = 50% S
y = 50% O
b) MH₃PO₄ = 3AH + AP + 4AO = 3×1+31+4×16 = 98g/mol
raport de masa ⇒ H:P:O = 3:31:64
98 p.m.........3 p.m H........31 p.m P........64 p.m O
100g............x....................y....................z
x = 3×100/98 = 3,061 % H
y = 31/98×100 = 31,63 % P
z = 64/98×100 = 65,3 % O
c) MMg(OH)₂ = AMg + 2(AO+AH) = 24+2(16+1) = 58g/mol
raport de masa ⇒ Mg:O:H = 24:32:2 = 12:16:1
29 p.m........12 p.m Mg....16 p.m O.....1 p.m H
100g...................x......................y.............z
x = 12×100/29 = 41,379 % Mg
y = 55,172 % O
z = 3,44% H
pag. 69. Chenar 1:
a) MCaCO₃ = ACa+AC+3AO = 40+12+3×16 = 100g/mol
%Ca = mCa/MCaCO₃×100 = 40/100×100 = 40
%C = 12/100×100 = 12
%O = 48/100×100 = 48
b) MCaO = ACa+AO = 40+16 = 56g/mol
%Ca = 40/56×100 = 71,42
%O = 28,571
c) MCH₄ = AC+4AH = 12+4×1 = 16g/mol
%C = 12/16×100 = 75
%H = 25
d) MMgCl₂ = AMg + 2ACl = 24+2×35,5 = 95g/mol
%Mg = 24/95×100 = 25,26
%Cl = 74,73
pag. 69. Chenar 2:
a) MH₂O = 18g/mol
18g H₂O....................16g O
36g H₂O......................xg O
x = 16×36/18 = 32g O
b) MH₂SO₄ = 98g/mol
1 mol H₂SO₄...........................4×16 = 64g O
2 moli H₂SO₄...............................x = 128g O
c) 1 kmol = 1000 moli
0,15 kmoli = 150 moli
MSO₂ = 64g/mol
1 mol SO₂........................32g O
150 moli SO₂...................x = 4800g O = 4,8 kg O
pag. 69. Chenar 3:
a) MH₂O = 18g/mol
18g H₂O...................2g H
xg H₂O......................6g H
x = 18×6/2 = 54g H₂O
b) MPH₃ = AP+3AH = 31+3*1 = 34g/mol
34g PH₃.......................3g H
xg PH₃.........................6g H
x = 68g PH₃
c) MH₂CO₃ = 2AH + AC + 3AO = 2*1+12+3*16 = 62g/mol
62g H₂CO₃....................2g H
xg H₂CO₃......................6g H
x = 186g H₂CO₃
