Question

Am de facut de la 1 la 7. Daca este cineva care ma poate ajuta macar la cateva?

Answer 1

1. Na2CO3 ·xH2O
          ↓            ↓
      2,86g      22,4/22.4 ·18 = 18g
n = 2,86/M        2,86/(106+18x)..................1molH2O
                             1mol..................................x = (106+18x)/2,86 ⇒ x = 10
Na2CO3·10H2O ;  %H2O = 180·100/286 = 62,93%
2.  FeSO4 : 45,6g  n = 45,6/152 = 0,3 moli
FeSO4·xH2O : 83,4/(152+18x) = 0,3 ⇒x = 7   %Fe = 56·100/278 = 20,14%
3.  ·M = 250g/mol  %H2O = 5·18·100/250 = 36%
4.  CaSO4·xH2O     18x·100/(136+18x) = 20,93   138 + 18x = 86x   x = 2
5.  MnSO4·xH2O             MnSO4                      H2O
             ↓                             ↓                              ↓
       110,8g                       60,4 g                     50,4 g (2,8 moli)
110,8 g cristalohidrat.......................................2,8 moli H2O
(151 + 18x).......................................................x ⇒     x = 7  mH2O = 50,4g
6.  M = 322g/mol  n = 3 moli
%H2O = 10·18/322 = 55,9%    mH2O = 3·10·18 = 540g
7.  CaCl2   M = 111g/mol n = 50/111 = 0,45 moli  mH2O = 0,45·6·18 = 48,6g