Răspuns:
folosesti relatia
p= m,purx100/m,impur, pr care o foloseti in functie de datele problemei
1.
m,i=800g
m,p=720
calculeaza p !
2.
m,i=2000g
p =90%
calculeaza m,pur !
4.
m,i=10000g
p=98,5%
calculeaza m,p!
3=
m,i=2000g
p=90%
m,p= pxm,i/100g=90x2000/100g= 1800g masa pura
masa impuritate= masa impura-masa pura=2000-1800-> 200g
deci 2000g piatra vanata contine 1800g sulfat de cupru si 200g impuritati
Explicație: