Odpowiedź:
a) wodorotlenek cynku- Zn(OH)2
mZn(OH)2= 65u+ 2×(16u+ 1u)= 65u+ 2× 17u=99u
mO= 2×16u= 32u
99u------ 100%
32u---------x% => x%O= 32,32%
b) tlenek manganu(Vll)- Mn2O7
mMn2O7= 2× 55u+ 7× 16u= 110u+ 112u= 222u
mO= 7+ 16u= 112u
222u----------100%
112u------------x%O. x%O= 50,45%
c) węglan wapnia- CaCO3
mCaCO3= 40u+ 12u+ 3+16u= 100u
mO= 3×16u= 48u
100u----------100%
48u---------- x%O. => x%O=48%
d) kwas octowy- CH3COOH
mCH3COOH= 12u+ 3×1u+ 12u+ 16u+16u+1u=60u
mO= 2×16u= 32u
60u---------100%
32u-----------x%O. x%O= 53,33%
e) siarczan (Vl) wapnia- woda(1/2)- CaSO4 × 2H2O
mCaSO4 × 2H2O= 40u+ 32u+ 4× 16u+ 4×1u+ 2×16u= 40u+ 32u+ 65u+ 4u+ 32u= 173u
mO= 6×16u= 96u
173u-----------100%
96u----------x%O => x%O= 55,49%
Wyjaśnienie:
