1.

a)

K_2O+H_2O->2KOH

n_{K_2O}={18,8}/{94}=0,2(mol)

Theo PT: n_{KOH}=2n_{K_2O}=0,4(mol)

->C_{M\ KOH}={0,4}/{0,5}=0,8M

b)

2KOH+H_2SO_4->K_2SO_4+2H_2O

Theo PT: n_{H_2SO_4}=1/2n_{KOH}=0,2(mol)

->m_{dd\ H_2SO_4}={0,2.98}/{20\%}=98(g)

2.

a)

n_{Na_2O}={6,2}/{62}=0,1(mol)

Na_2O+H_2O->2NaOH

Theo PT: n_{NaOH}=2n_{Na_2O}=0,2(mol)

m_{dd\ spu}=6,2+193,8=200(g)

->C\%_{NaOH}={0,2.40}/{200}.100\%=4\%

b)

2NaOH+CuSO_4->Cu(OH)_2+Na_2SO_4

Theo PT: n_{Cu(OH)_2}=1/2n_{NaOH}=0,1(mol)

->a=m_{Cu(OH)_2}=0,1.98=9,8(g)

c)

Cu(OH)_2  $$\xrightarrow{t^o}$$  CuO+H_2O

CuO+2HCl->CuCl_2+H_2O

Theo PT: n_{HCl}=2n_{CuO}=2n_{Cu(OH)_2}=0,2(mol)

->V_{dd\ HCl}={0,2}/2=0,1(l)=100(ml)