Răspuns :
Cerință:
Calculați M pentru următoarele substanțe:
- trioxid de fosfor - P₂O₃;
- dioxid de sulf - SO₂;
- oxid de calciu - CaO;
- oxid de sodiu - Na₂O;
- hidroxid de magneziu - Mg(OH)₂;
- hidroxid de potasiu - KOH;
- acid carbonic - H₂CO₃;
- acid azotos - HNO₂;
- acid fosforic - H₃PO₄;
- hidrogen sulfurat - H₂S;
- azot - N₂;
- sulfat de cupru - CuSO₄;
- carbonat de sodiu - Na₂CO₃;
- sulfat de aluminiu - Al₂(SO₄)₃;
Răspuns:
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{P_2O_3}=110\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{SO_2}=64\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{CaO}=56\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{Na_2O}=62\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{Mg(OH)_2}=58\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{KOH}=56\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{H_2CO_3}=62\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{HNO_2}=47\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{H_3PO_4}=98\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{H_2S}=34\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{N_2}=28\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{CuSO_4 }=160 \dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{Na_2CO_3 }=106\dfrac{g}{mol}} [/tex]
[tex]\LARGE\color{red}\boxed{\bf \mathcal M_{Al_2(SO_4)_3}=342\dfrac{g}{mol}} [/tex]
Explicație:
Masa molară se calculează însumând masele atomice relative ale elementelor componente substanței. Se notează cu M și are unitatea de măsură g/mol.
Calcule:
[tex]\bf \mathcal M_{P_2O_3}=2\cdot A_{P}+3 \cdot A_{O}=2\cdot 31+3\cdot 16=62+48=110\dfrac{g}{mol} [/tex]
[tex]\bf \mathcal M_{SO_2}=A_{S}+2\cdot A_{O}=32+2\cdot16=32+32=64 \dfrac{g}{mol} [/tex]
[tex]\bf \mathcal M_{CaO}=A_{Ca}+A_{O}=40+16=56 \dfrac{g}{mol} [/tex]
[tex]\bf \mathcal M_{Na_2O}=2\cdot A_{Na}+A_{O}=2\cdot23+16=46+16=62 \dfrac{g}{mol}[/tex]
[tex]\bf \mathcal M_{Mg(OH)_2}=A_{Mg}+2\cdot A_{O}+2\cdot A_{H}=24+2\cdot16+2\cdot1=24+32+2=58 \dfrac{g}{mol} [/tex]
[tex]\bf \mathcal M_{KOH}=A_{K}+A_{O}+A_{H}=39+16+1=56 \dfrac{g}{mol} [/tex]
[tex]\bf \mathcal M_{H_2CO_3}=2\cdot A_{H}+A_{C}+3\cdot A_{O}==2\cdot1+12+3\cdot16=2+12+48=62 \dfrac{g}{mol} [/tex]
[tex]\bf \mathcal M_{HNO_2}=A_{H}+A_{N}+2\cdot A_{O}=1+14+2\cdot16=15+32=47 \dfrac{g}{mol} [/tex]
[tex]\bf\mathcal M_{H_3PO_4}=3\cdot A_{H}+A_{P}+4\cdot A_{O}=3\cdot1 +31+4\cdot16=3+31+64=98\dfrac{g}{mol} [/tex]
[tex]\bf\mathcal M_{H_2S}=2\cdot A_{H}+A_{S}=2\cdot1+32=2+32=34 \dfrac{g}{mol}[/tex]
[tex]\bf \mathcal M_{N_2}=2\cdot A_{N}=2\cdot14=28 \dfrac{g}{mol}[/tex]
[tex]\bf \mathcal M_{CuSO_4}=A_{Cu}+A_{S}+4\cdot A_{O}=64+32+4\cdot 16=96+64=160\dfrac{g}{mol}[/tex]
[tex]\bf \mathcal M_{Na_2CO_3}=2\cdot A_{Na}+A_{C}+3\cdot A_{O}=2\cdot23+12+3\cdot16=46+12+48=106 \dfrac{g}{mol} [/tex]
[tex]\bf \mathcal M_{Al_2(SO_4)_3}=2\cdot A_{Al}+3\cdot A_{S}+12\cdot A_{O}=2\cdot27+3\cdot32+12\cdot 16=54+96+192=342 \dfrac{g}{mol} [/tex]
Succes!
-Mihai
[tex] \sf P.S. \: Gliseaza \: spre \: stanga \: daca \: nu \: vezi \:intreg\: raspunsul. [/tex]