9.
дано
V(H2) = 6.5L
m(Al)-?
2Al+3H2SO4-->Al2(SO4)3+3H2
n(H2) = V(H2) / Vm = 6.5 / 22,4 = 0.29 L
2n(Al) = 3n(H2)
n(Al) = 2*0.29 / 3 = 0.193mol
M(Al) = 27 g/mol
m(Al) = n(Al) * M(al) = 0.193 * 27 = 25.11 g
ответ 25.11 г
10.
дано
m(ppa H2S) =150 g
W(H2S) =75%
m(PbS) -?
m(H2S) = 150 * 75% / 100% = 112.5 g
Pb+H2S-->PbS+H2
M(H2S) = 34 g/mol
n(H2S) = m/M = 112.5 / 34 = 3.31 mol
n(H2S) = n(PbS) = 3.31 mol
M(PbS) = 239 g/mol
m(PbS) = n(PbS) * M(PbS) = 3.31 * 239 = 791.09 g
ответ 791.09 г
6.
2Сu+S-->Cu2S
6Na+2H3PO4-->2Na3PO4+3H2
2Fe+3Br2-->2FeBr3
2N2+O2-->2N2O
CaCO3-->CaO+CO2
Объяснение:
2) +6
3) +3
4) +6
5) +6
6) +3