Verified answer

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