Question

DAU 56 DE PUNCTE + COROANA!

1. Sa se calculeze masa moleculara a urmatoarelor substante: H2Co3 , So2 , HCl , FeO, NH3 , H2S,HNo2 , So3 , MgCl2 , CaO.
2. Determinati raportul de masa zn; O din znO si raportul atomic.
3. Calculati compozitia procentuala a AgCl.
4. O substanta A contine 75,26% Ag si 24,74% clor. Determinati formula chimica a substantei A, stiind ca are masa moleculara M=143,5
5. Calculati masa de sulf din 244g acid sulfuric.
6. Calculati numarul de moli de azot care se afla in 48g monoxid de azot (NO).
7. Calculati masa de carbon care se afla in 6 moli Co2.
8. Determinati masa de acid clorhidric care contine 71 g clor.
9. Calculati masa pura de Ca Co3 din 268 kg CaCo3 de puritate 66%.
10. Calculati masa de impuritati care se afla in 680g MgCo3 ce contine 420g Mg Co3 pur. Se dau masele atomice: AH=1 , Ac=12 , Ao=16 , As=32 , ACl=35,5 , AFe=56 , An=14 , Amg=24 , Aca=40 , Azn=65 , Aag=108.

Answer 1

1. MH2CO3 = 2AH + AC + 3O = 2*1 +12 + 3*16 = 62g/mol
MSO2 = AS+2AO  = 32+2*16 = 64g/mol
MHCl = 36,5g/mol
MFeO = AFe + AO = 56+16 = 72g/mol
MNH3 = 17g/mol
MH2S = 34g/mol
MHNO2 = 47g/mol
MSO3 = 80g/mol
MMgCl2 = 95g/mol
MCaO = 56g/mol

2. raport masic ZnO = 65:16
raport atomic = 1:1

3.MAgCl = AAg+ACl = 143,5g/mol

%Ag = mAg/MAgCl*100 = 108/143,5*100 = 75,26
%Cl = 24,73

4. n Ag = %Ag*M/AAg*100 = 75,26*143,5/108*100 = 1 atom Ag
n Cl = %Cl*M/ACl*100 = 24,74*143,5/35,5*100 = 1 atom Cl

F.m => AgCl - clorura de argint

5. MH2SO4 = 98g/mol

98g H2SO4..................................32g S
244g H2SO4............................. x = 79,673g S

6.MNO = 30g/mol

30g NO.......................1 mol O
48g...........................x = 1,6 moli O

7. MCO2 = 44g/mol

1 mol CO2........................12g C
6 moli CO2.....................x = 72g C

8. MHCl = 36,5g/mol

36,5g HCl.......................35,5g Cl
x g HCl............................71g Cl

 x = 73g HCl

9. puritatea = masa pura/masa impura*100 => masa pura  = puritatea*masa impura/100 = 66*268/100 = 176,88kg CaCO3

10. masa impura = 680-420 = 260g MgCO3