Write a balanced equation for the reaction that occurs in
each of...

Question

Write a balanced equation for the reaction that occurs in
each of the following cases: (c) A fresh surface of lithium metal is exposed to oxygen gas.

Accepted Answer

hey everyone in this example, we're given the empirical formula for potassium oxide and we need to write out the balanced chemical equation for the reaction of potassium oxide and explain whether for potassium ions in the balanced equation. So we're going to look at the potassium oxide formula and we're going to break it down into the atoms that make up this compound. So recognize that we have the K potassium adam and then we have the oxygen atom in this compound where oxygen we want to recall always exists as a diatonic molecule. So it's going to have a subscript of two. Then we have our arrow and then on our product side we have our potassium oxide which has formed. Now we want to recognize that each of these atoms on our reactive side have ionic charges. So for our potassium because it's in Group one A on the periodic table, we want to recall that it has a plus one charge and our oxygen because it's in Group six A. On the periodic table has a minus to charge. Now because we have a subscript on our oxygen, we will have an overall charge where we multiply our subscript by our ion charge minus two and that's going to give us an overall charge of minus four. Now looking at these two charges, we can't cancel out positive one from minus four because that would only leave us with minus three and looking at our potassium oxide, this is a neutral compound, it has no charge. So we need to get rid of this minus four. And in order to do so we're going to place a coefficient of four in front of our potassium ions and that would be four times are plus one charge, which would give us an overall charge of plus four, Which would allow us to cancel out this -4, giving us our neutral compound potassium oxide. Now we want to make sure everything is balanced once we've added that coefficient and so on a reacting side, recognized that we have four potassium atoms and two oxygen atoms were on our product side. We currently have two potassium atoms and one oxygen atom. So to balance this out, we're going to place a coefficient of two in front of our potassium oxide so that now we have four potassium atoms matching both sides of our equation and two oxygen atoms matching both sides of our equation. And so now everything is balanced and this is going to complete the chemical equation for the formation of potassium oxide. And so I hope that it's clear now as to why we have four potassium ions. Again, it's because we need this potassium oxide to be a neutral compound. So we had to place a coefficient of four here to create a plus four charge so that we can cancel out this minus four charge from our di atomic oxygen. So if you have any questions please leave them down below, otherwise, I will see everyone in the next practice video

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