Test Objectives: Solutions
· Know that all solutions are classified as homogeneous mixtures
· Know that solutions are composed of 2 parts: solute & solvent
· Define the terms unsaturated, saturated & supersaturated
o Know that supersaturated solutions are unstable
o Be able to explain how to prepare a supersaturated solution
· Define the terms miscible & immiscible
· Be able to solve for any variable in Molarity (M) word problems
o Molarity = moles of solute
Moles of solution
· be able to convert mass of solute to moles before solving the word problems
· Be able to solve Molarity (M) in dilution word problems
· Be able to solve for any variable in the equations for % concentration (volume or mass) & ppm
o mass solution = mass solute + mass solvent
· Be able to describe the effect of polarity, temperature & pressure on the solubility of solids in liquids, liquids in liquids or gas in liquids
o remember: pressure only effects solubility of gases in liquids
o as temperature increases the solubility of solids tends to increase but the solubility of gases tends to decrease
· Know the factors that effect the rate of solution & why they effect the rate:
o temperature
o stirring or agitation
o surface area
· Be able to predict the solubility of non-polar, polar & ionic compounds in polar & nonpolar liquids
o rule of thumb: ‘like dissolves like’
o know that alcohols have characteristics of both polar & non-polar liquids but do not dissolve ionic compounds
· Determine how soluble a compound is at a given temperature using the solubility traces found in Table G
o use solubility curves to predict how much water is required to dissolve a given amount of solute at a given temp or how much solute will dissolve in a given amount of water
o be able to predict the amount of solute that will crystallize (precipitate) from solution when it is chilled
o use Table G to predict if a solution is saturated, unsaturated or supersaturated
· Determine whether a given compound will be soluble or insoluble in water using the guidelines in Table F.
· Know what makes a compound an electrolyte or a non-electrolyte
o in general ionic compounds are electrolytes & covalent compounds (except acids) are not
o know how to determine the number of ions a given ionic compound produces when it dissociates in solution
· Define the term collogative properties and know that it is the concentration of the particles that is important not the nature of the particles
· Describe the effects of a non-volatile solute on the freezing and boiling points of a liquid
o freezing point decreases, boiling point increases, vapor pressure decreases
o know that the effect on fp & bp is proportional to the number of particles in the solution
§ ex: 1M Na2SO4 has a greater effect than 1M NaCl
§ ex: 1M KBr has a greater effect than 0.5M KBr