Problem 123
What reaction, if any, occurs if a piece of copper metal is placed in an aqueous solution containing iron(II) sulfate?
Problem 124
A solution contains both copper(II) nitrate and lead(II) nitrate. What substance could be added to the solution to precipitate the lead(II) ions, but leave the copper(II) ions in solution? After removal of the lead(II) compound, what could then be added to the solution to precipitate the copper(II) ions?
Problem 125
Draw molecular-level diagrams to show that a solution of \(\mathrm{Kl}\) is a strong electrolyte and that a solution of \(\mathrm{CO}\) is a nonelectrolyte.
Problem 126
Write equations for reactions that could be used to release each of the following elements from their compounds. (a) \(\mathrm{O}_{2}\) (b) \(\mathrm{H}_{2}\) (c) \(\mathrm{Cl}_{2}\)
Problem 127
Identify a substance that could be used to release the following metals from their compounds, using a different substance for cach metal. (a) \(\mathrm{Cr}\) (b) \(\mathrm{Fe}\) (c) \(\mathrm{Al}\) (d) \(\mathrm{Pb}\)
Problem 128
Suggest chemical reactions that could be used to identify the contents of four unlabeled bottles containing solutions of the following substances: \(\mathrm{CuSO}_{4}, \mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}, \mathrm{~Pb}\left(\mathrm{NO}_{3}\right)_{2}\), and \(\mathrm{FeSO}_{4}\).
Problem 129
Suggest chemical methods that would separate the following ions or compounds from one another. (a) \(\mathrm{Fe}^{3+}\) and \(\mathrm{Al}^{3+}\) (b) \(\mathrm{Ba}^{2+}\) and \(\mathrm{Mg}^{2+}\) (c) \(\mathrm{Cl}^{-}\)and \(\mathrm{NO}_{3}{ }^{-}\) (d) \(\mathrm{BaSO}_{4}\) and \(\mathrm{MgSO}_{4}\)
Problem 130
When copper metal is exposed to the atmosphere over a long period of time, it takes on a green patina (a coating of copper compounds). The green color of copper roofs and the Statue of Liberty are examples. Initially the copper metal reacts with oxygen gas. The product of this reaction reacts in part with water vapor and in part with carbon dioxide in the air. Predict the products and write balanced equations for the three reactions.
