In this chapter we have seen that the reaction of

Chapter , Problem 1DE

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Problem 1DE

In this chapter we have seen that the reaction of potassium metal with oxygen leads to a product that we might not expect, namely, potassium superoxide, KO2(s). Let’s design some experiments to learn more about this unusual product.

(a) One of your team members proposes that the capacity to form a superoxide such as KO2 is related to a low value for the first ionization energy. How would you go about testing this hypothesis for the metals of group 1A? What other periodic property of the alkali metals might be considered as a factor favoring superoxide formation?

(b) KO2(s) is the active ingredient in many breathing masks used by firefighters because it can be used as a source of O2(g). In principle, KO2(s) can react with both major components of human breath, H2O(g) and CO2(g), to produce O2(g) and other products (all of which follow the expected patterns of reactivity we have seen). Predict the other products in these reactions and design experiments to determine whether KO2(s) does actually react with both H2O(g) and CO2(g).

(c) Propose an experiment to determine whether either of the reactions in part (b) is more important in the operation of a firefighter’s breathing mask.

(d) The reaction of K(s) and O2(g) leads to a mixture of KO2(s) and K2O(s). Use ideas presented in this exercise to design an experiment to determine the percentages of KO2(s) and K2O(s) in the product mixture that results from the reaction of K(s) with excess O2(g).