Chapter 20

The Dissolving Process

Part 1

Solutions

• Solutions are homogeneous mixtures.

Solutes and SolventsSolutes and Solvents• “solute” is what is being dissolved.• “solvent” is what it is dissolved in.

• If we make tea and mix sugar into it. The sugar and tea are the solutes. Water is the solvent. The sweet tea is the solution.

Water

• The universal solvent.

Air

• Air is a homogeneous mixture of gases.• Air is a solution of gases.

What is the solvent in air?

• The solvent is the major component in a solution.• All lesser components are solutes.

Miscibility

• Liquids that are soluble in each other in all proportions are miscible.

• Liquids can also be partially miscible or immiscible.

Solvation

• Solvation is the process of solvent particles attaching with particles of a solute. As solute dissolves in a solvent the solute particles spread out and become surrounded by solvent particles.

• If water is the solvent we call this process hydration.

Dissociation is a process in which ionic compounds separate or split into ions.

Like Dissolves Like

• like dissolves like" is an expression used by chemists to remember how some solvents work.

• It refers to "polar" and "nonpolar" solvents and solutes.

Water – Cooking Oil – Food Coloring.

• Water is Polar.

• What are the polarities of cooking oil and food coloring?

Cooking Oil is nonpolar. Food Coloring is polar.

Red Blood Cells

Crescent or sickle-shaped red blood cells (RBCs) are present with Sickle cell anemia, and stand out

clearly against the normal round RBCs.

Some solute-solvent combinations are: (solute state-solvent state)

• oxygen in nitrogen (gas-gas) = air• carbon dioxide in water (gas-liquid) = soda pop• water vapor in air (liquid-gas) = humidity• alcohol in water (liquid-liquid) = liquor• mercury in silver (liquid-solid) = dental amalgam• sugar in water (solid-liquid) = kool-aid• tin in copper (solid-solid) = bronze alloy• How many other combinations are possible?

Other solute – solvent combinations

• (solid-gas) = Mothballs sublime in air

• (gas-solid) = Hydrogen dissolves rather well in metals; an example is hydrogen in palladium which is used as a gas stove lighter.

Homework

• Worksheet: The Dissolving Process – You should be able to complete the front of

this worksheet.