Balance Redox Reaction Example Problem

Balance Redox Reaction Example Problem When balancing redox reactions, the overall electronic charge must be balanced in addition to the usual molar ratios of the component reactants and products. This example problem illustrates how to use the half-reaction method to balance a redox reaction in a solution. Question Balance the following redox reaction in an acidic solution: Cu(s) HNO3(aq) → Cu2(aq) NO(g) Solution Step 1: Identify what is being oxidized and what is being reduced. To identify which atoms are being reduced or oxidized, assign oxidation states to each atom of the reaction. For review: Rules for Assigning Oxidation StatesAssigning Oxidation States Example ProblemOxidation and Reduction Reaction Example Problem Cu(s): Cu 0HNO3: H 1, N 5, O -6Cu2: Cu 2NO(g): N 2, O -2 Cu went from oxidation state 0 to 2, losing two electrons. Copper is oxidized by this reaction.N went from oxidation state 5 to 2, gaining three electrons. Nitrogen is reduced by this reaction. Step 2: Break the reaction into two half-reactions: oxidation and reduction. Oxidation: Cu → Cu2 Reduction: HNO3 → NO Step 3: Balance each half-reaction by both stoichiometry and electronic charge. This is accomplished by adding substances to the reaction. The only rule is that the only substances you can add must already be in the solution. These include water (H2O), H ions (in acidic solutions), OH- ions (in basic solutions) and electrons. Start with the oxidation half-reaction: The half-reaction is already balanced atomically. To balance electronically, two electrons must be added to the product side. Cu → Cu2 2 e- Now, balance the reduction reaction. This reaction requires more work. The first step is to balance all atoms except oxygen and hydrogen. HNO3 → NO There is only one nitrogen atom on both sides, so nitrogen is already balanced. The second step is to balance the oxygen atoms. This is done by adding water to the side that needs more oxygen. In this case, the reactant side has three oxygens and the product side has only one oxygen. Add two water molecules to the product side. HNO3 → NO 2 H2O The third step is to balance the hydrogen atoms. This is accomplished by adding H ions to the side that needs more hydrogen. The reactant side has one hydrogen atom while the product side has four. Add 3 H ions to the reactant side. HNO3 3 H → NO 2 H2O The equation is balanced atomically, but not electrically. The final step is to balance the charge by adding electrons to the more positive side of the reaction. One the reactant side, the overall charge is 3, while the product side is neutral. To counteract the 3 charge, add three electrons to the reactant side. HNO3 3 H 3 e- → NO 2 H2O Now the reduction half-equation is balanced. Step 4: Equalize the electron transfer. In redox reactions, the number of electrons gained must equal the number of electrons lost. To accomplish this, each reaction is multiplied by whole numbers to contain the same number of electrons. The oxidation half-reaction has two electrons while the reduction half-reaction has three electrons. The lowest common denominator between them is six electrons. Multiply the oxidation half-reaction by 3 and the reduction half-reaction by 2. 3 Cu → 3 Cu2 6 e-2 HNO3 6 H 6 e- → 2 NO 4 H2O Step 5: Recombine the half-reactions. This is accomplished by adding the two reactions together. Once they are added, cancel out anything that appears on both sides of the reaction.   Ã‚  Ã‚  3 Cu → 3 Cu2 6 e- 2 HNO3 6 H 6 e- → 2 NO 4 H2O 3 Cu 2 HNO3 6H 6 e- → 3 Cu2 2 NO 4 H2O 6 e- Both sides have six electrons that can be canceled. 3 Cu 2 HNO3 6 H → 3 Cu2 2 NO 4 H2O The complete redox reaction is now balanced. Answer 3 Cu 2 HNO3 6 H → 3 Cu2 2 NO 4 H2O To summarize: Identify the oxidation and reduction components of the reaction.Separate the reaction into the oxidation half-reaction and reduction half-reaction.Balance each half-reaction both atomically and electronically.Equalize the electron transfer between oxidation and reduction half-equations.Recombine the half-reactions to form the complete redox reaction.

Free Essays on The Interview

Booker T. Washington (1856-1915). Up from Slavery: An Autobiography. 1901. VI. Black Race and Red Race DURING the year that I spent in Washington, and for some little time before this, there had been considerable agitation in the state of West Virginia over the question of moving the capital of the state from Wheeling to some other central point. As a result of this, the Legislature designated three cities to be voted upon by the citizens of the state as the permanent seat of government. Among these cities was Charleston, only five miles from Malden, my home. At the close of my school year in Washington I was very pleasantly surprised to receive, from a committee of white people in Charleston, an invitation to canvass the state in the interests of that city. This invitation I accepted, and spent nearly three months in speaking in various parts of the state. Charleston was successful in winning the prize, and is now the permanent seat of government. 1 The reputation that I made as a speaker during this campaign induced a number of persons to make an earnest effort to get me to enter political life, but I refused, still believing that I could find other service which would prove of more permanent value to my race. Even then I had a strong feeling that what our people most needed was to get a foundation in education, industry, and property, and for this I felt that they could better afford to strive than for political preferment. As for my individual self, it appeared to me to be reasonably certain that I could succeed in political life, but I had a feeling that it would be a rather selfish kind of success-individual success at the cost of failing to do my duty in assisting in laying a foundation for the masses. 2 At this period in the progress of our race a very large proportion of the young men who went to school or to college did so with the expressed determination to prepare themselves to be great lawyers, or Congressm... Free Essays on The Interview Free Essays on The Interview Booker T. Washington (1856-1915). Up from Slavery: An Autobiography. 1901. VI. Black Race and Red Race DURING the year that I spent in Washington, and for some little time before this, there had been considerable agitation in the state of West Virginia over the question of moving the capital of the state from Wheeling to some other central point. As a result of this, the Legislature designated three cities to be voted upon by the citizens of the state as the permanent seat of government. Among these cities was Charleston, only five miles from Malden, my home. At the close of my school year in Washington I was very pleasantly surprised to receive, from a committee of white people in Charleston, an invitation to canvass the state in the interests of that city. This invitation I accepted, and spent nearly three months in speaking in various parts of the state. Charleston was successful in winning the prize, and is now the permanent seat of government. 1 The reputation that I made as a speaker during this campaign induced a number of persons to make an earnest effort to get me to enter political life, but I refused, still believing that I could find other service which would prove of more permanent value to my race. Even then I had a strong feeling that what our people most needed was to get a foundation in education, industry, and property, and for this I felt that they could better afford to strive than for political preferment. As for my individual self, it appeared to me to be reasonably certain that I could succeed in political life, but I had a feeling that it would be a rather selfish kind of success-individual success at the cost of failing to do my duty in assisting in laying a foundation for the masses. 2 At this period in the progress of our race a very large proportion of the young men who went to school or to college did so with the expressed determination to prepare themselves to be great lawyers, or Congressm...