дано
m(P) = 12.4 g
V(O2) -?
n(P2O5) -?
4P+5O2-->2P2O5
M(P) =31 g/mol
n(P) = m/M =12.4 / 31 = 0.4 mol
4n(P) = 5n(O2)
n(O2) = 0.4 * 5 / 4 = 0.5 mol
V(O2) = Vm*n = 22.4 * 0.5 = 11.2 L
4n(P) = 2n(P2O5)
n(P2O5) = 0.4 * 2 / 4 = 0.1 mol
ответ 11.2 л, 0.1 моль
4.
дано
m(P2O5) = 56.8 g
n(P) - ?
4P+5O2-->2P2O5
M(P2O5) = 142 g/mol
n(P2O5) = m/M = 56.8 / 142 = 0.4 mol
n(P) = 4*0.4 / 2 = 0.8 mol
ответ 0.8 моль
5.
дано
m(Fe3O4) = 5.3 g
V(H2)-?
Fe3O4+4H2-->3Fe+4H2O
M(Fe3O4) = 232 g/mol
n(Fe3O4) = m/M = 5.3 / 232 = 0.023 mol
n(Fe3O4) = 4n(H2)
n(H2) = 0.023 * 4 = 0.092 mol
V(H2) = n*Vm = 0.092 * 22.4 = 2.06 L
ответ 2.06 л
Объяснение:
m'(p-pa NaCl) = 250 r
ω'(NaCl) = 15% или 0,15
+m(NaCl) = 150 r
Найти:
ω"(NaCl) -?
m'(NaCl) = 250 r*0.15 = 37.5 r
m"(NaCl) = 37,5 r + 150 r = 187,5 r
m"(p-pa NaCl) = 250 r + 150 r = 400 r
ω"(NaCl) = 187,5 r/400 r *100% = 46.88%
ответ: 46,88%