[tex]m_{CaO}=500g[/tex] (masa impura)
[tex]P=90[/tex]%
[tex]P=\frac{m_{pur}}{m_{impur}}*100=\ \textgreater \ m{pur}=\frac{P*m_{impur}}{100}=\frac{90*500}{100}=90*5=450g[/tex] CaO
[tex]M_{CaO}=40+16=56g/mol[/tex]
[tex]n=\frac{m(pur)}M={450}{56}=8.03[/tex] moli CaO
