Which of the following is the expected product of the reaction of K(s) and H 2 (g)? (i) KH(s), (ii) K 2 H(s), (iii) KH 2 (s), (iv) K 2 H 2 (s), or (v) K(s) and H 2 (g) will not react with one another.

Welcome back everyone. We need to identify the chemical formula of the product of the reaction between solid calcium and oxygen gas and the conditions are being under heat. So we're going to place a delta sign over our reaction arrow, recall that in this synthesis reaction we have calcium which is located in Group two A. Of our periodic table corresponding to forming a two plus caddy on charge. And oxygen. On the other hand, we find in group six A. Of our periodic table corresponding to a two minus an eye. On that oxygen forms. So recall that for our reaction, we're going to have to swap our subscript of our ions, meaning that we would have see A two and then again when we swap our eye on charges, but we should see that we have a common factor here are common factor Is our subscript of two for both of our atoms. And so we would divide by two in this formula. So see a 2.02. We would divide by the Common factor of two. And this will then simplify to see A. O. As our final formula, since the twos will cancel when we divide both by two. And so for our final answer, we can complete our reaction so that calcium oxide is our product formed. Note that we have two moles of oxygen on the reaction side, so we'll actually produce two moles of calcium oxide to balance this equation. And so the correct choice is going to be choice A and the multiple choice. So I hope this made sense. And let us know if you have any questions.

Ch.7 - Periodic Properties of the Elements

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Brown 14th Edition

Ch.7 - Periodic Properties of the Elements

Problem 102

Chapter 7, Problem 102

Which of the following is the expected product of the reaction of K(s) and H₂(g)? (i) KH(s), (ii) K₂H(s), (iii) KH₂(s), (iv) K₂H₂(s), or (v) K(s) and H₂(g) will not react with one another.

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Identify the reactants: Potassium (K) is a metal and Hydrogen (H2) is a diatomic non-metal gas.

Consider the reactivity of potassium: Potassium is an alkali metal, which are known to react with hydrogen to form metal hydrides.

Write the balanced chemical equation for the reaction: Potassium reacts with hydrogen gas to form potassium hydride (KH). The balanced equation is 2K(s) + H2(g) -> 2KH(s).

Analyze the possible products: From the balanced equation, the expected product is potassium hydride (KH), which corresponds to option (i).

Conclude that the other options (ii, iii, iv, v) do not represent the expected product based on the chemical properties and typical reactions of potassium with hydrogen.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Reactivity of Alkali Metals

Alkali metals, such as potassium (K), are highly reactive, especially with nonmetals like hydrogen (H). When alkali metals react with hydrogen gas, they typically form metal hydrides. This reactivity is due to their low ionization energy, which allows them to easily lose their outermost electron and form positive ions.

Formation of Metal Hydrides

Metal hydrides are compounds formed when metals react with hydrogen. In the case of potassium, the expected product is potassium hydride (KH). This compound consists of potassium ions (K+) and hydride ions (H-), showcasing the typical stoichiometry of one metal atom reacting with one hydrogen molecule.

Stoichiometry of Chemical Reactions

Stoichiometry involves the calculation of reactants and products in chemical reactions based on the conservation of mass. In the reaction between potassium and hydrogen, the balanced equation indicates that two potassium atoms react with one hydrogen molecule to produce two units of potassium hydride (2K + H2 → 2KH). Understanding stoichiometry is essential for predicting the correct products of a reaction.

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Related Practice

Textbook Question

Hydrogen is an unusual element because it behaves in some ways like the alkali metal elements and in other ways like nonmetals. Its properties can be explained in part by its electron configuration and by the values for its ionization energy and electron affinity. (a) Explain why the electron affinity of hydrogen is much closer to the values for the alkali elements than for the halogens.

Textbook Question

The first ionization energy of the oxygen molecule is the energy required for the following process: O21g2¡O2 +1g2 + e- The energy needed for this process is 1175 kJ>mol, very similar to the first ionization energy of Xe. Would you expect O2 to react with F2? If so, suggest a product or products of this reaction.

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Textbook Question

It is possible to define metallic character as we do in this book and base it on the reactivity of the element and the ease with which it loses electrons. Alternatively, one could measure how well electricity is conducted by each of the elements to determine how 'metallic' the elements are. On the basis of conductivity, there is not much of a trend in the periodic table: Silver is the most conductive metal, and manganese the least. Look up the first ionization energies of silver and manganese; which of these two elements would you call more metallic based on the way we define it in this book?

Which of the following is the expected product of the reaction of K(s) and H2(g)? (i) KH(s), (ii) K2H(s), (iii) KH2(s), (iv) K2H2(s), or (v) K(s) and H2(g) will not react with one another.

Verified video answer for a similar problem:

Key Concepts

Reactivity of Alkali Metals

Formation of Metal Hydrides

Stoichiometry of Chemical Reactions

Which of the following is the expected product of the reaction of K(s) and H₂(g)? (i) KH(s), (ii) K₂H(s), (iii) KH₂(s), (iv) K₂H₂(s), or (v) K(s) and H₂(g) will not react with one another.