Question

A substance such as \(\mathrm{NaCl}\) dissolves in water because the strong ionic forces that exist in solid \(\mathrm{NaCl}\) can be overcome by, and replaced by, forces between ________ and the ions.

Short answer

A substance such as NaCl dissolves in water because the strong ionic forces that exist in solid NaCl can be overcome by, and replaced by, forces between \(water molecules\) and the \(ions\).

Step-by-step solution

Identify the forces present in solid NaCl

In solid sodium chloride (NaCl), there are strong ionic forces between the positively charged sodium ions (Na+) and the negatively charged chloride ions (Cl-). These forces are electrostatic attractions holding the ions together, forming a lattice structure.

Understand the properties of water

Water (H2O) is a polar solvent, meaning it has an uneven distribution of charge. The oxygen atom in water is more electronegative than the hydrogen atoms, resulting in a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms. This makes water molecules capable of interacting with charged particles.

Identify the forces that can replace the ionic forces in NaCl when it dissolves in water

When NaCl dissolves in water, the strong ionic forces between Na+ and Cl- are overcome and replaced by forces between the water molecules and the ions. These forces are known as ion-dipole forces. The partially positive hydrogen atoms in water molecules are attracted to the negatively charged chloride ions (Cl-), while the partially negative oxygen atoms in water molecules are attracted to the positively charged sodium ions (Na+). These ion-dipole forces enable NaCl to dissolve in water. So, the answer to complete the given statement is: A substance such as NaCl dissolves in water because the strong ionic forces that exist in solid NaCl can be overcome by, and replaced by, forces between #tag_answer#water molecules and the ions#tag_end_answer#.

Key concepts

Ionic Forces

In the world of chemistry, understanding the basics of how substances interact is fundamental. One such interaction occurs within ionic compounds like sodium chloride (NaCl), where ionic forces play a major role. These forces are also known as electrostatic attractions, which are the glue that holds the positively and negatively charged ions together. In solid NaCl, these forces create a rigid lattice structure, keeping each ion in place. To envision this, imagine a highly organized dance of oppositely charged partners firmly holding onto each other.

However, this steadfast arrangement can be disrupted. Just as a new song can change the dance, introducing a polar solvent like water can change the dynamics between the ions. Understanding how ionic forces contribute to the solubility of compounds such as NaCl is crucial for students tackling chemistry problems.

Polar Solvents

When it comes to dissolving salts like NaCl, not all liquids are created equal. Enter the world of polar solvents, with water being the quintessential example. Water is often referred to as the 'universal solvent' for a reason; its molecules have a lopsided electrical charge that makes them extraordinary at dissolving ionic compounds.

The key lies in the structure of the water molecule. The oxygen atom hoards more of the shared electrons, becoming partially negative, while the hydrogen atoms are left with a slight positive charge. This polar nature allows water to surround and interact with various ions, prying them away from the solid structure where they reside. For students, visualizing water molecules as tiny magnets, pulling apart the ions in a salt crystal, can be a helpful analogy.

Ion-Dipole Forces

To better understand the dissolution process, we delve into the role of ion-dipole forces. These are attractions between the charged ions of a salt and the partial charges on a polar solvent like water. When NaCl is introduced into water, each Na+ ion becomes surrounded by water molecules with the oxygen side facing the Na+, due to its partial negative charge. Simultaneously, each Cl- ion is surrounded by water molecules with the hydrogen side facing the Cl-, because of its partial positive charge.

This interaction replaces the ionic bonds that held the solid crystal together, effectively dissolving the salt. For students, it might be useful to imagine each ion being given a new dance partner, the water molecules, leading them away into the solution. Grasping how ion-dipole forces facilitate the dissolution of ionic compounds is essential for chemistry learners.