1)
дано
m1(ppa KCL) = 120 g
W1(KCL) = 15%
+m(KCL) = 20 g
W2(KCL)-?
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)3)-?
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
