Question

1.Sa se calculeze masa moleculara a următoarelor substante:MgCL2,AgNO3, H2S, KCL,FeO,ZnO, PbS,Na2SO4,H2CO3, CH4
2Determinati raportul de masa Na:O:H,si raportul atomic din hidroxid de sodiu NaOH
3Calculati nr de moli de calciu care se afla in 112 g oxid de calciu,CaO
4Calculati masa de carbon care se afla in 10 moli de CO2. Va rog repede dau coroana

Answer 1

1. M MgCl2= A Mg + 2×A Cl = 24+2×35,5=24+71=95 (95g /mol)
M AgNO3= A Ag + A N + 3× A O =108+14+3×16 =108+14+ 48= 170 g /mol
M H2S =2× A H + A S = 2×1+32= 2+32= 34 g/mol
M KCL= A K +A Cl = 39+35, 5=74,5 g /mol
M FeO= A Fe+A O = 56+16=72 g /mol
MZnO= A Zn + A O =65+16=81 g/mol
M PbS= A Pb+A S =207+32= 239 g/mol
M Na2SO4= 2× A Na +A S +4×A O = 2×23+32+4×16= 46+32+64=142 g/mol
M H2CO3 = 2× A H + A C + 3× A O = 2×1+12+3×16 = 2+12+48=62 g /mol
M CH4= A C + 4× A H = 12+4×1=12+4=16 g/mol

2
Raportul de masa
Na:O:H = 23:16:1
Raportul atomic
Na:O :H =1:1:1

3.
M CaO = A Ca +A O =40+16=56 g/mol
1 mol CaO............... 56g
x moli CaO.............. 112 g
1/x=56/112=>x=2 moli

4.
M CO2= A C +2× A O =12+2×16=12+32=44 g /mol
1 mol CO2.............. 44g
10 moli CO2........... xg
1/10= 44/x=>x=440 g
44g CO2......... 12g C
440 g CO2........ xg C
44/440=12/x =>x=120 g C