Chapter 15 Forming Solutions  Recall a solution is a homogeneous mixture of a solute and a solvent.  The substance present in the largest amount is the solvent.  The solute solvent combination can be any state: solid, liquid, or gas.  If water is the solvent, it is referred to as an aqueous solution.

The Dissolving Process  When an ionic substance dissolves water separates the cation from the anion and both become the solute in the solution.  Soluble ionic compounds are more attracted to the polar water molecule than to the ionic complement in the crystal.  Insoluble ionic compounds are more attracted to each other than to the water molecule.

The Dissolving Process  Molecular solutes dissolve in water if they have similar bonding characteristics as polar water.  Ethanol, C 2 H 5 OH, dissolves in water because the O-H bond is similar in polarity to the O-H bond in water.  “Likes dissolve like”  Oil is a non-polar substance made with non polar bonds between C and H so it is NOT soluble in water.

“Dry” Cleaning Dry Cleaning uses a non-polar solvent to dissolve the dirt and substances from your clothes. Many fabrics require this type of solvent. Dry Cleaning uses a non-polar solvent to dissolve the dirt and substances from your clothes. Many fabrics require this type of solvent. Tetrachloroethylene Cl 2 C=CCl 2 is used for the dry cleaning of fabrics. It is non-polar because the molecule is symmetric and the electrons are shared more equally than in water. Tetrachloroethylene Cl 2 C=CCl 2 is used for the dry cleaning of fabrics. It is non-polar because the molecule is symmetric and the electrons are shared more equally than in water.

Concentration Terms  Unsaturated More solute can be put into the solution. More solute can be put into the solution.  Saturated The maximum amount of solute is placed in the solution. The maximum amount of solute is placed in the solution.  Supersaturated More than the maximum amount of solute is placed in the solution. More than the maximum amount of solute is placed in the solution.

Saturation  A solution is said to be saturated when you have the maximum amount of solute in the solvent.  At the point of saturation the solvent no longer has the availability to break apart the solute.  If more solute is placed in the solution a state of dynamic equilibrium is reached.  The additional solute will dissolve, however the dissolved solute will fall out of the solution at the same rate.

Supersaturation  Changing the temperature of the solution will affect the amount of solute allowed in the solvent.  Increasing the temperature will increase the solubility of endothermic dissolving processes.  Most solids are endothermic like this.  Decreasing the temperature will increase the solubility of exothermic dissolving processes.  Most gases are exothermic like this.  A solution becomes supersaturated by saturating it then lowering/raising the temperature.

Vitamins  Water soluble (polar) vitamins like Vitamin C are water soluble and can be taken daily without concern. Your body excretes any excess though the kidneys.  Fat soluble (nonpolar) vitamins like Vitamin A are fat soluble and are stored in the tissue. It is possible to overdose on fat soluble vitamins because your body has a harder time removing the excess.  Follow recommended amounts!

Homework  Terms Chapter 14  Pg. 555 [4-11]