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Ch.9 Solutions
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 9, Problem 31d

Predict whether each of the following ionic compounds is soluble in water:
d. K2O

Verified step by step guidance
1
Identify the ions that make up the compound K₂O. Potassium (K⁺) is a Group 1 metal, and oxygen (O²⁻) is the anion.
Recall the solubility rules for ionic compounds. One key rule is that all compounds containing Group 1 metal cations (such as K⁺) are soluble in water.
Apply the solubility rule to K₂O. Since it contains the Group 1 metal potassium (K⁺), the compound is expected to be soluble in water.
Consider any exceptions to the solubility rules. In this case, there are no exceptions that apply to K₂O, so the compound remains soluble.
Conclude that K₂O is soluble in water based on the solubility rules and the absence of exceptions.

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Key Concepts

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

Ionic Compounds

Ionic compounds are formed when atoms transfer electrons, resulting in the formation of positively and negatively charged ions. These compounds typically consist of a metal and a non-metal, and their properties include high melting and boiling points, as well as electrical conductivity when dissolved in water.
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Solubility Rules

Solubility rules are guidelines that help predict whether an ionic compound will dissolve in water. Common rules include that most alkali metal compounds and nitrates are soluble, while many carbonates and phosphates are not. Understanding these rules is essential for determining the solubility of specific compounds.
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Potassium Oxide (K₂O)

Potassium oxide (K₂O) is an ionic compound formed from potassium ions (K⁺) and oxide ions (O²⁻). According to solubility rules, compounds containing alkali metals, such as potassium, are generally soluble in water. Therefore, K₂O is expected to react with water to form potassium hydroxide (KOH), which is soluble.
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