The Solution Process

Chemistry

Mrs. Coyle

Solution

A homogeneous mixture. One phase.

Stainless Steel (Fe, Cr, Ni)

Solute, Solvent

• Solute—the substance being dissolved.

• Example: When you dissolve CuCl2 in water, CuCl2 is the solute.

• Solvent- the substance that dissolves the solute.

• Example: water

Aqueous Solution

• A solution that has water as the solvent.

• Possible substances that can dissolve in water: Ionic compounds Polar covalent compounds

Solvation

The surrounding of solute particles by solvent particles.

Dissociation of Ionic Compounds

the process by which an ionic compound separates into its ions as it dissolves.

Dissociation of NaCl in Water

Dissociation of NaCl

Movie Clip- Dissociation of Salt in Water

http://www.youtube.com/watch?v=EBfGcTAJF4o

“Like dissolves like”

Solvent Solute Is Solution Likely?

Polar Polar Yes

Polar Nonpolar No

Nonpolar Polar No

Nonpolar Nonpolar Yes

Polar ethanol molecule is dissolved by the polar water molecule. Ethanol remains intact.

Will sugar dissolve in water?

Will petroleum dissolve in water?

Oil on water- 2 phases

Will ionic compounds conduct electric current when dissolved in water? Yes

Why?

Electrolytes and Non-electrolytes

Electrolytes: conduct an electric current when in the molten state or in aqueous solution. Ionic compounds

Non-electrolytes do not conduct a current. Usually molecular compounds

Is sugar C6H12O6 electrolyte?

Do all electrolytes conduct electricity to the same degree? Weak electrolytes: partially ionize in water

and conduct electricity in solution poorly (ex. Ammonia)

Strong electrolytes: fully ionize in water and conduct electricity in solution strongly(ex. NaCl).

Hydrate:

A crystalline compound in which the ions are attached to one or more water molecules.

Example:

CuSO4•5H2O copper(II) sulfate pentahydrate

Prefixes for naming Hydrates

mono- 1 di- 2 tri- 3 tetra- 4 penta- 5

hexa- 6 hepta- 7 octa- 8 nona- 9 deca- 10

Analyzing Hydrates

Simulation click on the link below: http://www.chem.iastate.edu/group/Green

bowe/sections/projectfolder/flashfiles/stoichiometry/empirical.html

Problem

Calculate the percent by mass of water in washing soda (Na2CO3

. 10 H2O) % mass of H2O = MM water x100 %

MM Hydrate

Answer: 62.9%

Efflorescent Hydrates

Hydrates that have high vapor pressures compared to water.

When the vapor pressure of the surrounding is lower than the vapor pressure of the hydrate, the hydrate will lose its water; it effloresces.

Hygroscopic Hydrates and Dessicants Hydrates that have a low vapor pressure

compared to water. These hydrates can absorb water from the

air. These can be used as dessicants (ex.

CaSO4).

Deliquescent

Materials that absorb so much water that they will become wet (form solutions). Ex. NaOH.

Part II Heterogeneous Aqueous Systems

Colloids and Suspensions

Heterogeneous Mixtures

Suspension

A mixture whose particles are temporarily suspended in a medium, but eventually settle down.

Particle size>100nmEx: dust in air.

Colloid A mixture whose particles (of size ~1 to

~100nm) are dispersed through a continuous medium. (The word colloid means “glue-like”)

Heterogeneous because there are distinct phases.

Tyndall Effect: Scattering of light.

Tyndall Effect

Types of Colloids

Aerosol: liquid or solid in dispersed in gases (fog, smoke).

Foam: gas in liquid (whipped cream). Emulsion: both substances are liquids

(mayonnaise). Sol: solid in liquid (jelly)