90 likes | 212 Views
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.
E N D
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, C2H5OH, 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. • Tetrachloroethylene Cl2C=CCl2 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. • Saturated • The maximum amount of solute is placed in the solution. • Supersaturated • 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]