1)
дано
m(ppa H2SO4) =200 g
W(H2SO4) = 15%
----------------------------
m(H2O)-?
m(H2SO4) = 200 * 15% / 100% = 30 g
m(H2O) = m(ppa H2SO4) - m(H2SO4) = 200 - 30 = 170 g
ответ 170 г
2) дано
m(ppa KOH) = 300 g
W(KOH) = 30%
-------------------
m(KOH) - ?
m(KOH) = m(ppa KOH) *W(KOH) / 100% = 300 * 30% / 100% = 90 g
ответ 90 г
3)
дано
m(Zn) = 13 g
+HCL
----------------
V(H2)-?
N(H2)-?
Zn+2HCL-->ZnCL2+H2
M(Zn) = 65 g/ mol
n(Zn) = m/M = 13 / 65 = 0.2 mol
n(Zn) = n(H2) = 0.2 mol
V(H2) =n(H2) * Vm = 0.2 * 22.4 = 4.48 L
N(H2) = n(H2) * N(A) = 0.2 * 6.02*10^23 = 1.204 *10^23 молекул
ответ : 4.48 L, 1.204 *10^23 молекул
4)
дано
m(ppa NaOH) = 200 g
W(NaOH) = 20 %
+CuS
------------------------------------
m(Cu(OH))-?
m(NaOH) = 200 * 20% / 100% = 40 g
2NaOH+CuS--> Cu(OH)2+Na2S
M(NaOH) = 40 g/mol
n(NaOH) = m/M = 40 / 40 = 1 mol
2n(NaOH) = n(Cu(OH)2)
n(Cu(OH)2) = 1 / 2 = 0.5 mol
M(Cu(OH)2) = 98 g/mol
m(Cu(OH)2) = n*M = 0.5 * 98 = 49 g
ответ 49 г