CHAPTER STUDY GUIDE CHEMISTRY SPRING FINAL

SOLUBILITY AND SOLUTIONS Factors that affect solubility -Solute-Solvent Interactions -Pressure Effects (dissolving gases) -Temperature Effects (for both gaseous and solid solutes) Solution -A solution is a homogenous mixture when one substance (solute) is dissolved into another (solvent). -An aqueous solution is dissolved in water. -They are a physical change. -There are no new substances being produced. -The particles of the solute and solvent merely physically mix and do not undergo a chemical change.

SOLUTE VS. SOLVENT -A solute is the substance to be dissolved such as sugar. It is usually a solid and is the smaller part of the solution. -The solvent is the one doing the dissolving such as water. It accepts the solute. The most common is H20, meaning most solutions are aqueous. -In a solution of salt and water, salt is the solute and water is the solvent.

DISSOLUTION AND ELECTROLYTES Rates of Dissolution -The rate of dissolution quantifies the speed of the dissolution process. -It depends on the nature of the solvent and solute, temperature, degree of under saturation, presence of mixing, and surface area. Electrolytes -An electrolyte is a substance that dissolves in water to give a solution that conducts electric current -When ionic solids dissolve in water, the positive and negative ions separate from each other and are free to move around. -Electrolytes can be strong (all pieces dissociate into ions) or weak (some form ions some don’t).

SATURATED VS. UNSATURATED, DILUTE VS. SUPERSATURATED, MISCIBLE AND IMMISCIBLE Saturated vs. Unsaturated -Saturated contains the maximum amount of solute for a given quantity of solvent at a constant temperature and pressure. -Unsaturated contains less solute than a saturated solution at a given temperature and pressure. Dilute vs. Supersaturated -Dilute is very few particles in the solution. -Supersaturated contains more solute than it can theoretically hold at a given temperature. Miscible and Immiscible -Two liquids are miscible if they dissolve in each other in all proportions. -Liquids that are insoluble in one another are immiscible.

MOLARITY -Molarity is an exact way to represent concentration. -Molarity (M) = # moles of solute in 1 L of solution -Molarity (M)= # moles of solute (mol) volume of solution (L) When given g and L and asked to find M use: M= mol V When given mol and L and asked to find V use: V= mol x M When given M and L and asked to find mol use: mol= V x M

MOLARITY PRACTICE PROBLEM Calculate the molarity when 75.0 grams of MgCl 2 is dissolved in mL of solution. *Convert mL to L (mLx1000) *Use molar mass to find moles. Then divide by volume to find M.

CONCENTRATION -A solution be changed either by adjusting the volume or the solute. -Adding solvent will dilute concentration. -Removing solvent increases concentration. -Formula to help: MiVi=MfVf -i= initial, f=final *pay attention to initial and final volumes when doing change in concentration problems

CONCENTRATION PRACTICE PROBLEM A student pours 60mL of 2.0 HCl acid into a beaker containing 240 mL of water. What is the new concentration of this acid? *Be sure to use correct final volume.