Grantham University Chemistry Assignment chapter 9

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Assignment Chapter 9

Concept Explorations

9.23. Forming Ionic Compounds

a. Consider a metal atom, which we will give the symbol M. Metal M can readily form the M⁺ cation. If the sphere on the left below represents the metal atom M, which of the other three spheres would probably represent the M⁺ cation? Explain your choice.

b. Consider a nonmetal atom, which we will give the symbol X. The element X is a gas at room temperature and can easily form the X-anion. If atom X is represented by the sphere on the left below, which of the other three spheres would probably represent the X-anion. Explain your choice.

c. On the basis of the information given previously, write a balanced chemical equation for the reaction that occurs when metal M reacts with nonmetal X. Include state symbols for the reactants and products.

d. Is the product of the reaction of M and X a molecule or an ionic compound? Provide justification for your answer.

e. Which of the representations below is the most appropriate to describe the compound of M and X, according to your answer for part d? Explain how you arrived at your choice.

9.24. Bond Energy

When atoms of the hypothetical element X are placed together, they rapidly undergo reaction to form the X₂ molecule:

a. Would you predict that this reaction is exothermic or endothermic? Explain.

b. Is the bond energy of X₂ a positive or a negative quantity? Why?

c. Suppose ΔH for the reaction is −500 kJ/mol. Estimate the bond energy of the X₂ molecule.

d. Another hypothetical molecular compound, Y₂(g), has a bond energy of 750 kJ/mol, and the molecular compound XY(g) has a bond energy of 1500 kJ/mol. Using bond-energy information, calculate ΔH for the following reaction: