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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 3

Describe the formation of an aqueous KI solution, when solid KI dissolves in water.

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1
Identify the chemical formula of potassium iodide (KI), which is an ionic compound composed of potassium (K⁺) and iodide (I⁻) ions.
Understand that when solid KI is added to water, the polar water molecules interact with the ions in the KI crystal lattice.
Explain that the partial positive charge on the hydrogen atoms of water molecules attracts the negatively charged iodide ions (I⁻), while the partial negative charge on the oxygen atoms of water molecules attracts the positively charged potassium ions (K⁺).
Describe how these interactions cause the KI crystal lattice to break apart, allowing the individual K⁺ and I⁻ ions to become surrounded by water molecules (a process called hydration).
Conclude that the result is an aqueous solution of KI, where the K⁺ and I⁻ ions are dispersed uniformly throughout the water, forming a homogeneous mixture.

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Key Concepts

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

Dissolution Process

The dissolution process involves the interaction between solute and solvent molecules. When solid KI (potassium iodide) is added to water, the polar water molecules surround the KI crystals, breaking the ionic bonds between potassium (K+) and iodide (I-) ions. This process results in the ions dispersing uniformly throughout the solution, creating an aqueous solution.
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Ionic Compounds in Water

Ionic compounds, like KI, consist of positively and negatively charged ions. In water, the polar nature of water molecules allows them to effectively solvate these ions. The positive end of water molecules attracts the iodide ions, while the negative end attracts the potassium ions, facilitating their separation and movement into the solution.
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Concentration of Solutions

The concentration of a solution refers to the amount of solute dissolved in a given volume of solvent. In the case of an aqueous KI solution, the concentration can be expressed in terms of molarity, which is moles of KI per liter of solution. Understanding concentration is essential for predicting the properties and behavior of the solution, such as its conductivity and reactivity.
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