Chpt 13: Properties of Solutions Flashcards Preview

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Flashcards in Chpt 13: Properties of Solutions Deck (51):
1

Solvation

attractive interaction of solvent molecules with the solute

2

Hydration

what you call the attractive interaction of solvent molecules with the solute WHEN THE SOLVENT IS WATER

Involves polar interactions (between the water molecules and the compound)

3

dissolution

when a solvent and a solute form a solution;

when a solute (like a sugar cube or some other NON electrolyte) goes into solution but isn't ionized

Not the same thing as dissociation!

4

solution

when one substance disperses uniformly in another; homogenous mixture

can be liquid, solid, or gas

5

dissociation

when a solute (like a salt cube or some other electrolyte) goes into solution and IS ionized

6

enthalpy vs enthalpy of rxn

enthalpy = total q (in a system)
enthalpy of rxn = total q per mole

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enthalpy of solution

q gained or lost in formation of solution

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entropy

thermodynamic quantity that describes the randomness of dispersal in space

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enthalpy change that favors solution formation

negative/exothermic

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entropy change that favors solution formation

positive

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2 scenarios that favor of sln formation

1. positive entropy change
2. negative enthalpy change (exothermic)

12

Equilibrium

what you get when a solution-creating rxn is done but there is still a fair amount of dissociated AND non-dissociated solute left over

weak electrolytes achieve equilibrium; strong electrolytes never achieve equilibrium

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2 simultaneous processes of equilibrium

dissolution
crystallization

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crystallization

1 of 2 simultaneous processes of equilibrium

when molecules, ions, or atoms come together to form a crystalline solid.

15

Saturated solution

when a solution at equilibrium has undissolved solute

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Unsaturated solution

a sln that has LESS solute than what is needed to achieve equilibrium

no undissolved solute left

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Supersaturated solution

a sln that has more solute than what is needed to achieve equilibrium

considered unstable

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Solubility

amt of solute needed to form a saturated sln at a given temp, assuming that excess solute is present

amt that something dissolves in a given quantity of solvent

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Miscible

liquids that will mix together in all proportions

liquids that dissolve well in one another

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Immiscible

liquids that will NOT mix together in all proportions

liquids that don't dissolve well in one another

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Henry's Law (on solubility)

formula: Sg = kPg

when a gas is above a sln, the concentration of gas molecules that get pushed into a liquid sln is proportional to the pressure exerted on the sln by the gas above it

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4 Ways to express concentration of slns

1. mass percent
2. parts per million
3. parts per billion
4. mole fraction

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moLALity

moles (of solute) per kg (of solvent)

not the same as molarity

24

Colligative properties

physical properties (of solutions) that depend on the ratio solute particles to solvent molecules

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4 of the colligative properties

FOBoV bruh?!

1. Freezing point lowering
2. Osmotic pressure
3. Boiling point elevation
4. Vapor-pressure lowering

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Ideal (solution)

describes slns that obey Raoult's law, including total uniformity in intermolecular interactions

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Dalton's law of partial pressures

that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases:

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Partial pressure

the pressure exerted by any of the gases in a mixture of gases;

the pressure that each gas in a mixture of gases contributes to the overall gas pressure

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Partial pressure formula

P​Total​​ = P​gas 1​​ + P​gas 2​​ + P​gas 3​​ ...

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Volatile/volatility

a quantity; expresses the tendency of a substance to vaporize (r/t vapor pressure).

Higher temp & higher vapor pressure = higher volatility

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molal boiling point elevation constant

Property of solvents that tells you how much its boiling point is raised when it has solutes mixed into it

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molal freezing point depression constant

Property of solvents that tells you how much its freezing point is lowered when it has solutes mixed into it

33

van't Hoff factor

The number of fragments that a solute break up into for a particular solvent

represented by "i"

ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass.

For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1.

34

osmotic pressure

pressure that must be applied to a sln to stop osmosis from bringing pure solvent into into the sln

minimum pressure which needs to be applied to a solution to prevent the inward flow of water across a membrane.

quantity for the tendency of a solution to take in water by osmosis

Expressed in unit of gas pressure

35

Colloid

mixture with microscopic particles in it that are bigger than molecules but too small for the naked eye

is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance

exp. oils, antibodies, enzymes

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Tyndell effect

property/ability of colloids to scatter visible light

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Brownian movement

random motion of particles suspended in a fluid (a liquid or a gas) resulting from their collision with the fast-moving atoms or molecules in the gas or liquid.

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Energetics

The properties of something in terms of energy

39

hydrate

a compound, typically a crystalline one, in which water molecules are chemically bound to another compound or an element (even after the aq water is evaporated off)

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Dynamic Equilibrium

when the rate of dissolution and crystallization in a solution are equal, and the amount of solute stays the same

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Vapor pressures

Pressure exerted by a vapor on the surface of a sln when the two are at dynamic equilibrium

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Boiling point

the temp at which a liquid achieves vapor pressure of 1 atm

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Triple point

The temp at which a solid, liquid, and vapor phase exist in equilibrium

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Ione pair

What you call previously dissociated ions (like Na+ and Cl-) that have re-combined temporarily (bc of electrostatic attraction) in a sln, causing a slight shift the van't Hoff "i" value

More common in diluted slns

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4 Things that impact solubility

1. Temp
2. Pressure (for gases)
3. Solute's intermolecular forces
4. Solute's lattice energy

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4 types of forces that matter in slns
(from weakest to strongest

1. (London) dispersion forces
2.dipole: dipole forces
3.hydrogen bonding
4. ion:dipole forces
5.ionic bonding

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(London) dispersion forces

1 of 5 types of intermolecular forces

attraction between all molecules once they get close enough together to est. a temporary dipole

weakest attraction

48

dipole: dipole forces

1 of 5 types of intermolecular forces

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hydrogen bonding

1 of 5 types of intermolecular forces

occurs between molecules that have a H attached to an F, O, or N & lone pair electrons to OTHER molecules that have a H attached to an F, O, or N & lone pair electrons

50

ion:dipole forces

1 of 5 types of intermolecular forces

attraction between ions and polar molecules (like water)

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ionic bonding (r/t intermolecular forces)

1 of 5 types of intermolecular forces

strongest attraction