I have no idea how to do the balanced equations portion of the FR. I know how to balance equations using stoichiometric coefficients, but not the particular type of "balanced equations" on the AP test. For example: "a small piece of sodium is placed in distilled water" my initial thinking: Na + H2O --> NaOH + H+ but they have as the right answer: 2Na + 2H2O --> 2Na+ + 2OH- + H2 Why is my answer wrong? (I have the right species and my answer is balanced...) Also, I have no idea when to combine certain species, or keep them separate as ions--do solubility rules account for this? Any ideas?