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46 Cards in this Set
- Front
- Back
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What are solutions |
Homogeneous mixtures of 2 or more pure substances |
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Solvent |
Component of greatest amount *All others are solutes |
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Aqueous solutions |
Contain water as the solvent and either gas liquid or solid as the solute |
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Saturated solution |
The solvent holds as much solute as is possible with the temperature |
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Solubility |
The solubility of a given solute is the max amount of the solute that can dissolve in a given amount of solvent at a specific temperature |
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Unsaturated solution |
Less solute than can dissolve in the solvent at that temperature is dissolved in the solvent |
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Supersaturated |
Solvent holds more solute than is normally possible at that temperature - these solutions are unstable -crystallization can usually be stimulated |
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Mass percentage: |
Mass of a = mass of a in solution/total mass of solution x 100 |
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Parts Per Million |
ppm=mass of a in solution/total mass of solution x10^6 |
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Parts Per Billion |
ppb=mass of a in soution/total mass of solution x 10^9 |
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Mole Fraction |
Xa= moles of a/ total moles of all components |
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What is the highest sum of mole fractions of all components |
1 |
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Is Molality temperature dependent |
No because moles and mass DO NOT change with temperature |
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What are the 2 factors that depends on the ability of substances to form solutions |
1. Natural tendency of substances to mix and spread into larger volumes 2.The types of intermolecular interactions involved in the solution process |
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What type of process is the mixing of gasses and does it or does it not occur with input of energy |
The mixing of gasses is spontaneous and occurs WITHOUT ant input of energy from OUTSIDE the system |
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Entropy |
Directly related to the number of ways a system can disperse its energy which is related to the freedom of motion of the particles |
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Entropy in a solid |
Particles are fixed: little freedom of motion |
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Entropy in a liquid |
Particles can move around and have greater freedom of motion |
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Entropy in a gas |
Particles have little restriction and much more freedom of motion |
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Fact on entropy |
The more freedom of motion they have the more they can distribute their kinetic energy |
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Does a solution have a higher or lower entropy than the pure solute and pure solvent |
A solution has HIGHER entropy because the # of ways to distribute the energy is related to the # of interactions btwn different molecules |
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Fact |
Gasses spontaneously mix however when its a solid or liquid the intermolecular forces become important in determining whether or not a solution forms |
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Solute-Solute interactions |
Must be OVERCOME in order to disperse the solute particles throughout the solvent |
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Solvent-Solvent interactions |
Must be OVERCOME to make room for the solute particles in the solvent |
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Solvent-Solute interactions |
Must OCCUR as the particles mix |
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Solvation |
The interaction between solute and solvent molecules |
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When the solvent is water the interactions are called: |
Hydration |
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What are the principle type of solute solvnet interaction in a solution of KCl in water |
Ion Dipole interaction |
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3 Processes that affect the energetics of a solution |
1. Separation of solute particles 2. Separation of solvent particles 3. New interactions between solute and solvent |
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Hess's Law |
ΔHsol =ΔHsolute + ΔHsolvent + ΔHmix |
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"likes dissolve likes" |
Substances with similar types of intermolecular forces dissolve in eachtother |
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Does acetone dissolve in water |
Yes, because they both are polar molecules, they mix in all proportions. |
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Does hexane dissolve in water |
No, Hexane is a nonpolar hydrocarbon and doesnt dissolve in water |
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The relationship between P and gas solubility is expressed by Henrys Law |
Sg = kPg -S(g) is the solubility of gas -K henrys law constant for that gas is that solvent -P(g) is the partial pressure of the gas above the liquid |
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The solubility of a solid solute in liquid solvents _______ with _______ temperature |
Increases, Increases The opposite occurs for gasses |
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Colligative properties |
Physical properties of solutions that depend on only the number of solute particles present in the solution. NOT on the identity of the solute particles. |
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Among colligative properties 4 examples |
1.Vapor pressure lowering 2.Boiling point elevation 3. Freezing point depression 4. Osmotic pressure |
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Lower vapor pressure equals ____ boiling point |
Higher |
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What does a phase diagram display |
The state of a substance at various pressures and temperatures and the places where equilibrium exist between phases |
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Lower vapor pressure means ______ boiling point |
higher Why? Need increased kinetic energy |
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The change in freezing point can be used using the fromula |
DeltaTf = Kf * m Kf=molal freezing point constant Delta Tf is a + quantity obtained by subtracting the freezing point of the solution from the freezing point of the pure solvent |
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Osmosis |
Movement of a solvent molecule through a semipermeable membrane to equalize solution concentrations on both sides of the membrane |
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During osmosis, net movement goes from ____ concentration to ______ concentration |
Higher solvent to Lower solvent |
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Osmotic pressure |
pie=(n/V)RT= MRT M is molarity R= ideal gas constant n=number of moles T=Kelvin temp V=volume |
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Hypertonic |
Solute concentration outside the cell is greater than inside the cell |
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Hypotonic |
Solute concentration outside the cell is less than inside the cell |
