Question

Answer 1

Câu 22 : 

Zn + 2HCl → ZnCl2 + H2

n Zn = n H2 = 11,2/22,4 = 0,5(mol)

n HCl = 2n H2 = 1(mol)

Suy ra:

m Zn = 0,5.65 = 32,5(gam)

V dd HCl = 1/2 = 0,5(lít)

Câu 23 : 

CuO + H2 $\xrightarrow{t^o}$ Cu + H2O

n Cu = n CuO = 16/80 = 0,2(mol)

=> m Cu = 0,2.64 = 12,8(gam)

Câu 24 : 

m NaOH = 200.20% = 40(gam)

m dd NaOH 50% = 40/50% = 80(gam)

Answer 2

Câu 25 : 

n H2SO4 = 0,2.2,5= 0,5(mol)

m H2SO4 = 0,5.98 = 49(gam)

m dd H2SO4 = 49/50% = 98(gam)