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Wfoxy618
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3.Determinati raportul numarului de atomi si raportul de masa pentru: a) H20; b) HCI 4.Cate grame reprezinta: a) 2 moli acid sulfuric; b) 0,5 moli sulfat de calciu. 5.Cati moli reprezinta: a) 50g MgO; b) 149g KCI. 6. Calculati compozitia procentuala din mase molare sau moleculare pentru urmatoarele substante: a) acid carbonic (H2CO3); b) amoniac (NH3). 7. In ce masa de hidroxid de calciu, se gasesc 60g Ca? 8. In cate grame de apa si acid fosforic se gasesc 6g de hidrogen?​

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3.

a) H2O

r.at. H:O=2:1

r.m H:O=2:16=1:8

b) HCl

r.at.H:Cl=1:1

r.m H:Cl=1:35,5

4.

MH2SO4=2x1+32+4x16=98g/mol

m=nxM=2x98=196gH2SO4

b) MCaSO4=40+32+4x16=136g/mol

m=nxM=0,5x136=68gCaSO4

5.

MMgO=24+16=40g/mol

n=m/M=50/40=1,25moli MgO

b) MKCl=39+35,5=74,5g/mol

n=m/M=149/74,5=2moli KCl

6.

MH2CO3=2x1+12+3x16=62g/mol

62gH2CO3...................2gH.............12gC..............48gO

100gH2CO3....................x%H..............y%C.............z%O

x=100x2/62=calculeaza

y=100x12/62=calculeaza

z=100x48/62=calculeaza

b) MNH3=14+3X1=17g/mol

17gNH3............14gN...............3gH

100MH3.............t%N....................v%H

t=100x14/17=claculeaza

v=100x3/17=claculeaza

7.

MCa(OH)2=40+2x16+2x1=74g/mol

74gCa(OH)2.................40gCa

xgCa(OH)2....................60gCa

x=60x74/40=calculeaza

8.

MH2O=2x1+16=18g/mol

18gH2O....................2gH

xgH2O.....................6gH

x=6x18/2=calculeaza

MH3PO4=3x1+31+4x16=98g/mol

98gH3PO4.....................3gH

yg H3PO4........................6gH

y=6x98/3=claculeaza

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