Caai 7 :
a) C2H4 + Br2 $\to$ C2H4Br2
b) Theo PTHH : n C2H4 = n Br2 = 8/160 = 0,05(mol)
%V C2H4 = 0,05.22,4/2,24 .100% = 50%
%V CH4 = 100% -50% = 50%
Câu 8 :
a) C2H5OH = a(mol) => n CH3COOH = 2a(mol)
$C_2H_5OH + Na \to C_2H_5OH + \dfrac{1}{2}H_2$
$CH_3COOH + Na \to CH_3COONa + \dfrac{1}{2}H_2$
Theo PTHH :
n H2 = 1/2 n C2H5OH + 1/2 n CH3COOH = 0,5a + a = 3,36/22,4 = 0,15
=> a = 0,1
=> m = 0,1.46 + 0,1.2.60 = 16,6(gam)
b)
$C_2H_5OH + CH_3COOH \buildrel{{H_2SO_4,t^o}}\over\rightleftharpoons CH_3COOC_2H_5 + H_2O$
Ta thấy : n C2H5OH < n CH3COOH nên hiệu suất tính theo số mol C2H5OH
n CH3COOC2H5 = n C2H5OH pư = 0,1.80% = 0,08(mol)
m este = 0,08.88 = 7,04(gam)