25. 電解硫酸銅水溶液,欲得到2莫耳銅,須電量多少庫侖?(假設法拉第常數=F庫) (A) 8F (B) 4 F (C) 2 F (D) F

27. 設\( \vec{A} = 2\hat{i} + 6\hat{j} - 3\hat{k} \), \( \vec{B} = 4\hat{i} + 2\hat{j} + \hat{k} \),求其向量差\( \vec{D} = \vec{A} - \vec{B} \)為多少? = (A)\(6\hat{i} + 8\hat{j} - 2\hat{k}\) (B) \( -2\hat{i} + 4\hat{j} - 4\hat{k} \)(C)\(2\hat{i} - 4\hat{j} + 4\hat{k}\)(D)\(8\hat{i} + 12\hat{j} - 3\hat{k}\)