1)
дано
m1(ppa kcl) = 120 g
w1(kcl) = 15%
+m(kcl) = 20 g
w2(
m1(kcl) = 120*15% / 100% = 18 g
m( общ kcl) = m1(kcl) + m(kcl) = 18+20 = 38 g
m( общ ppa kcl) = 120 + 20 = 140 g
w2(kcl) = m( общ kcl) / m( общ ppa kcl) * 100% = 38 / 140 * 100% = 27.14%
ответ 27.14%
2)
дано
m(ppa naoh) = 56 g
w(naoh) = 5%
+al(no3)3
m(al(oh)
m(naoh) = 56*5% / 100% = 2.8 g
3naoh+al(no3)3--> 3nano3+al(oh)3
m(naoh) = 40 g/mol
n(naoh) = m/m = 2.8 / 40 = 0.07 mol
3n(naoh) = n(al(oh)3)
n(al(oh)3) = 0.07 / 3 = 0.023 mol
m(al(oh)3) = n*m = 0.023 * 78 = 1.82 g
ответ 1.82 г
2SO2 + O2 = 2SO3
S(+4)-2e = S(+6) 2 в-ль
O(0) +2e = O(-2) 2 ок-ль
2ZnS + 3O2 = 2ZnO + 2SO2
S(-2)-6e = S(+4) 2 в-ль
O2(0) +4e = 2O(-2) 3 ок-ль
2KCl + F2 = 2KF + Cl2
2Cl(-) -2e = Cl2(0) 1 в-ль
F2(0) +2e = 2F(-) 1 ок-ль
Сa + 2H2O = Ca(OH)2 + H2
Ca(0)-2e = Ca(+2) 1 в-ль
2H(+) +2e = H2(0) 1 ок-ль
4Mg + 9HNO3 = 4Mg(NO3)2 + NH3 + 3H2O
Mg(0) -2e = Mg(+2) 4 в-ль
N(+5) +8e = N(-3) 1 ок-ль