I am having a lot of trouble understanding acid-base reactions. I was able to struggle through most of the homework, but I'm not usre about these questions.
1) Can an acidic solution be made less acidic by adding an acidic solution?
2) Pennies manufactured after 1982 are made of zinc metal, Zn, within a coat of copper metal, Cu. Zinc is more easily oxidzed than copper. Why, then, don't these pennies quickly corrode?
Is this because the copper has more of an affinity for the underlying zinc than the oxygen around it?
3) Chemical equations need to be balanced not only in terms of the number of atoms, but also by the charge. In other words, just as the same number of atoms should appear before and after the arrow of an equation, so should the same charge. Take this into account to balance the following chemical equation:
Sn2+ + Ag ----> Sn + Ag+
The charge looks balanced to me. There is a positive charge on the left and the right. All I see is that an Sn atom is missing on the left. So maybe the equation should read:
Sn2+ + Ag --- Sn + SnAg+ ?
Thanks for your help - this is my last homework assignment in this class, and I can tell I won't be pursuing chemistry or physics in my studies - lol!
1. If you add a more dilute acid, the ...
2. Copper and zinc form brass, which does not corrode. AT the juncture of the Zn-Cu interface, brass is formed.
3.Balancing by electrons and mass is a complication. In yours, you have two electrons missing on the left (the Sn+2, on only one on the right...so where did the electron come from. I would balance it this way..
Sn+2+2Ag>>Sn + 2Ag+1
all that means is each of the Ag atoms donated one electron to the Sn+2 ion
It is now balanced in mass, and in charge.
If you want extra credit, figure out why brass is non-corrosive.
Perhaps brass is noncorrosive because the zinc and copper are locked into an alloy, or solid solution, that will not release any electrons to allow for oxidation?
Thanks for the help, too! :-) Mary
I can help you with understanding acid-base reactions and answer your questions. Let's go through each question one by one:
1) Can an acidic solution be made less acidic by adding an acidic solution?
No, adding an acidic solution to an acidic solution will not make it less acidic. In fact, it will make the solution more acidic. To make an acidic solution less acidic, you need to add a basic solution. Acids and bases react together in a neutralization reaction, where the acidic and basic properties cancel each other out, resulting in a less acidic or basic solution.
2) Pennies manufactured after 1982 are made of zinc metal, Zn, within a coat of copper metal, Cu. Zinc is more easily oxidized than copper. Why, then, don't these pennies quickly corrode? Is this because the copper has more of an affinity for the underlying zinc than the oxygen around it?
The reason these pennies don't quickly corrode is due to a phenomenon called galvanic corrosion or galvanic coupling. When zinc comes into contact with oxygen and moisture, it corrodes and forms zinc oxide. However, the presence of copper in the outer layer of the penny creates a protective barrier. Copper has a higher affinity for oxygen compared to zinc, so it reacts with the oxygen and forms copper oxide. This copper oxide layer acts as a protective coating, preventing further oxidation of the underlying zinc. Hence, the copper layer protects the zinc from corrosion.
3) The chemical equation you provided, Sn2+ + Ag ----> Sn + Ag+, is not balanced in terms of charge and atoms. To balance chemical equations, you need to ensure that the number of atoms and their charges are the same on both sides of the equation.
The balanced equation is:
Sn2+ + 2Ag ----> Sn + 2Ag+
In this equation, both sides have a charge of +2, and the number of tin (Sn) atoms and silver (Ag) atoms are equal on both sides. The coefficient of 2 in front of Ag on the right side balances the equation in terms of atoms.
I hope this helps you understand the concepts better and assists you in completing your homework. If you have any more questions, feel free to ask!