Răspuns:
Explicație:
Ca3(PO4)2
1)
in molecula sunt 3 atomide Ca, 2 de P si 8 de O
Ca : P : O = 3 : 2 : 8
2)
3*40 : 2*31 : 8*16
120 : 62 : 128
3)
M Ca3(PO4)2 = 120 + 62 + 128 = 310 g/mol
310 g Ca3(PO4)2...............120 g Ca .................62 g P ....................128 g O
100 g..............................................x..........................y....................................z
x = 120*100/310 = 38,7% Ca
y = 62*100/310 = 20% P
z = 128*100/310 = 41,3% O
4)
310 g Ca3(PO4)2...............120 g Ca
a.............................................20 g Ca
a = 20*310/120 = 51,7 g Ca3(PO4)2
5)
310 g Ca3(PO4)2......................128 g O
200 g..............................................b
b = 200*128/310 = 82,6 g O
