Câu 5 :
a)
$n_{NaOH} = 0,1.2,5 = 0,25(mol)$
$m_{NaOH} = 0,25.40 = 10(gam)$
b)
$C_{M_{CaCl_2}} = \dfrac{0,02}{0,2} = 0,1M$
c)
$C\%_{NaCl} = \dfrac{6}{6 + 144}.100\% = 4\%$
Câu 6 :
a) $2Na + 2H_2O \to 2NaOH + H_2$
$n_{H_2} = \dfrac{3,36}{22,4} = 0,15(mol)$
$n_{NaOH} = 2n_{H_2} = 0,3(mol)$
$m_{NaOH} = 0,3.40 = 12(gam)$
b)
$CuO + H_2 \xrightarrow{t^o} Cu + H_2O$
$n_{Cu} = n_{H_2} = 0,15(mol)$
$m_{Cu} = 0,15.64 = 9,6(gam)