化學平衡~~chem~~~~

CH3COOH 的摩爾質量 = 12x2 + 1x4 + 16x2 = 60 g/mol
C2H5OH 的摩爾質-12x2 + 1x6 + 16 = 46 g/mol

CH3­COOH(l) + C2H5OH(l) ⇌ CH3COOC2H5(l)+ H2O(l)

開始時：
CH3COOH 的摩爾數 =25 x 1.049 / 60 = 0.4371 mol
C2H5OH 的摩爾數 =25 x 0.789/46 = 0.4288 mol

滴定時：
CH3COOH(aq) + NaOH(aq) → CH3COONa(aq) + H2O(l)
所用 NaOH 的摩爾數 =3 x (10/1000) = 0.03 mol
10 cm³ 混合物含 CH3COOH的摩爾數 = 0.03 mol
50 cm³ 混合物含 CH3COOH的摩爾數 = 0.03 x (50/10) = 0.15 mol

平衡時：
CH3COOH 的摩爾數 = 0.15mol
C2H5OH 的摩爾數 = 0.4288- (0.4371 - 0.15) = 0.1417 mol
CH3COOC2H5 的摩爾數 =0.4371 - 0.15 = 0.2871 mol
H2O 的摩爾數 =0.2871 mol

平衡常數 Kc
= ([CH3COOC2H5] x [H2O]) / ([CH3COOH]x [C2H5OH])
= [(0.2871/50) x (0.2871/50)] / [(0.15/50) x (0.1417/50)]
= (0.2871 x 0.2871) / (0.15 x 0.1417)
= 3.88