P->P4O10->H3PO4->Na3PO4->Ca3(PO4)2
1)4P+5O2=P4O10
2)P4O10+6H2O=4H3PO4
3)H3PO4+3NaOH=Na3PO4+3H2O
4)2Na3PO4+3Ca(NO3)2=Ca3(PO4)2+6NaNO3
K₂SO₄+Na₂SO₄+2BaCl₂=2KCl+2NaCl+2BaSO₄
K₂SO₄+BaCl₂=2KCl+BaSO₄
174 233
x a=233x/174
Na₂SO₄+BaCl₂=2NaCl+BaSO₄
142 233
y b=233y/142
233x/174+233y/142=233
x+y=158
x=K₂SO₄=87 г., y=Na₂SO₄=71 г.
ω(K₂SO₄)=87/158, ω(Na₂SO₄)=71/158
14.2
15.3?
16 3
17.2
18.2,5
19.3
20.2
Дано:
w(Br2)-1,6%
V(c3h4)-1,12л
Найти:
m(br2)-?
C3H4+2Br=C3H4Br4
n(c3h4)=1.12/22,4=16г
m(Br2)=0, was *160=16 г
16г-100%
х г-1,6%
Тогда
х=0,256г