Cate grame de Ca se gasesc in 250g CaCO3 de puritate 80%?

Răspuns :

[tex]m_{CaCO_3 \ pur}=\frac{80*250g}{100}=200g[/tex]

[tex]M_{CaCO_3}=40+12+3*16=100g/mol[/tex]

[tex]100g \ CaCO_3..........40g \ Ca[/tex]

[tex]200g \ CaCO_3...........x \ g \ Ca[/tex]

[tex]\frac{100}{200}=\frac{40}{x}[/tex]

[tex]x=\frac{200*40}{100}=80g[/tex]