4. 平衡在酸中的反應 H2O2(aq)+Cr2O72-(aq)→Cr3+(aq)O2(g) 後，所有整數係數和最小為多少？ (A) 12 (B) 16 (C) 20 (D) 24

11. 下列敘述何者正確？ (A) The 2s orbital is the same size as the 3s orbital. (B) The process of adding more solvent to a solution is called concentration. (C) Mixtures can be separated into pure substances by various means including distillation and filtration. (D) The electrolysis of water produces H2 gas at the anode and O2 gas at the cathode.