# Hint 2 balance hydrogen by adding hydrogen ions given

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Hint 2. Balance hydrogen by adding hydrogen ions Given this partially balanced half-reaction $$\rm 3H_2O+I^- \rightarrow IO_3{^-}$$ how many $$\rm H^+$$ ions should be added to the right side of the equation to balance hydrogen? 3 3 Express your answer numerically as an integer. Hint 1. Determine how many hydrogen atoms are on the left side of the equation How many hydrogen atoms are currently shown on the left side of this equation? $$\rm 3H_2O+I^- \rightarrow IO_3{^-}$$ Express your answer numerically as an integer. Hint 3. Determine the number of electrons How many electrons are needed on the more positive side of the equation to balance the charge? $$\rm 3H_2O+I^- \rightarrow IO_3{^-}$$ Express your answer numerically as an integer. Part C Use steps 3 and 4 listed in the introduction to rewrite this unbalanced half-reaction $$\rm Cl_2 \rightarrow Cl{^-}$$ such that it is balanced with respect to mass and charge. Do not include phases in your answer. Express your answer as a chemical equation. Use the symbol e - for an electron. what coefficient should be placed in front of $$\rm Cl^-$$ to balance the chlorine atoms? Express your answer numerically as an integer. ANSWER: 3 3
Correct Combining half-reactions Since these half-reactions must occur together, the number of electrons lost in the oxidation half-reaction must equal the number gained in the reduction half- reaction. Make the number of electrons in both half-reactions equal by multiplying one or both half-reactions by a small whole number. Finally, sum the two half- reactions. Part D Given these balanced half-reactions $$\rm 3H_2O+I^- \rightarrow IO_3{^-}+6H^++6e^-$$ $$\rm Cl_2+2e^- \rightarrow 2Cl^-$$ enter the overall balanced redox reaction in an acidic solution. Do not include phases in your answer. Enter your answer as a chemical equation. Hint 1. Balance the electron transfer Given these half-reactions $$\begin{array}{l}\rm A & \rm 3H_2O+I^- & \rightarrow & \rm IO_3{^-}+6H^++6e^- \cr \rm B & \rm Cl_2+2e^- & \rightarrow & \rm 2Cl^- \end{array}$$ what must be done to balance the electron transfer? ANSWER: Hint 2. How to add two reactions If these two example reactions are added together $$\begin{array}{l} \rm A & \rightarrow & \rm B+e^- \cr \rm X+e^- & \rightarrow & \rm Y \end{array}$$ the result is $$\rm A+X+\cancel{\rm e^-} \rightarrow \rm B+\cancel{\rm e^-}+Y$$ where the cancelled electrons are omitted from the overall equation. ANSWER: Correct Item 4 First launch this video . During the video, you’ll be asked a conceptual question about the example. After watching the video, answer the related questions at the right. You can watch the video again at any point. Part A