High School Chemistry - Core Concept Cheat Sheet

19: Solutions
Key Solution Terms Concentrations of Solution
 Solution: Homogeneous mixture. The solution formation % by mass: % mass  mass solute  100
involves the breaking and forming of intermolecular forces. mass solution
Solution = Solute + Solvent.
The mass units must match!
 Solute: Substance being dissolved (in smaller amount).
 Solvent: Substance doing the dissolving (in larger % by volume: % volume  volume solute  100
amount). volume solution
Solute vs Solvent Mnemonic: Dissolve solute into The volume units must match!
solvent = “Police came, the thief hide the lute in the vent.”
 Unsaturated Solution: The solution can hold more solute % mass/volume: % mass / volume  mass solute
100
particles. volume solution
 Saturated Solution: The solution is holding as many The volume unit is mL.
solute particles as it can.
Molarity (M): Molarity  moles solute
 Supersaturated Solution: The solution contains more L solution
solute particles than it should be able to at that
temperature. A solution can become supersaturated by
raising the temperature, which allows more solute to Molality (m): Molality  moles solute
dissolve, and then lowering the temperature slowly back kg solvent
down. Molarity vs Molality Mnemonic: MolaRity (moles over Liter
 Concentration: ratio of solute to solvent or solution. solution) and MolaLity (moles over kg solvent) = “Rose to
Lover and Loyal to King!”
 Concentrated: high ratio of solute to solvent.
Calculations with Concentrations
 Solubility Curve: Graph showing the solubility of a solid at Dilution equation: M1V1 = M2V2
various temperatures. M1 = original molarity V1 = original volume
 Dilute: low ratio of solute to solvent. M2 = new molarity V2 = new volume
Volume units must match!
 Dilution: adding solvent to create a more dilute solution.
 Electrolyte: compounds dissociate into ions when Solution Stoichiometry:
dissolved in water. Allows solution to conduct electricity. Use molarity to form the equality between moles and liters of
a solution.
 Colloids: Solution with solute particles large enough to
exhibit the Tyndall Effect. Example: How many liters of 1.7M HCl are needed to react
 Tyndall Effect: The light is visible and scattered as it with 2.5 g Mg?
travels through the colloid.
2.5g Mg 1 mole 2 mole 1 L HCl
Mg HCl
Formation of Solutions = 0.12 L HCl
24.31 g 1 mole 1.7 mole
Steps for solution formation: Mg Mg HCl
1. “Expand the solvent”—break intermolecular forces within
the solvent. Electrolyte Solutions
2. “Expand the solute”—break intermolecular forces within
the solute. To break up into electrolytes:
3. Form new intermolecular forces between solute &  Leave polyatomic ions together.
solvent.  Use subscripts that are not a part of a polyatomic ion as
 Steps 1 & 2 require energy. Step 3 releases energy. coefficients.
 If the energy put in is much greater than the energy
released, the solution will not form. Examples:
NaNO3  Na+ + NO3-
Factors Affecting Solubility CaCl2  Ca2+ + 2 Cl-
“Like Dissolves Like”
 Molecules with “like” bond properties will form similar Colloids
intermolecular forces with each other as they did with Colloids - Solutions with large enough particles to scatter light.
themselves. Therefore, the energy released will be
similar to the energy put in.
Pressure: Tyndall effect:
 Gases dissolve more when there is a higher pressure of
the gas above the solution. For a solution:
Temperature:
 Gases dissolve more when the temperature of the
solution is lower. For a colloid:
 Most solids dissolve more when the temperature of the
solution is higher.
How to Use This Cheat Sheet: These are the keys related to this topic. Try to read through it carefully twice then recite it out on a
blank sheet of paper. Review it again before the exams.

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