Chapter 14: Solutions

when difference in EN is greater than 2, what bond is it?

ionic bond

heterogeneous mixture

Non-uniform composition

homogeneous mixture

uniform in composition, one distinct phase

when difference in EN is less than 2, what bond is it?

polar covalent bond

Spontaneous Mixing

when a barrier is removed, spontaneous mixing occurs, producing a solution of uniform concentration

Aqueous VS. Non-aqueous Solution

aqueous water is solvent, non anything but water

what is an ion-dipole interaction?

an attractive force between charged ion and polar molecule

what is a H bond?

Polar bond to H, only with N, O, or F

What is a dipole-dipole interaction?

Attractive forces between polar molecules.

What is an ion-induced dipole interaction?

charged ion approaches nonpolar molecule and induces a dipole moment

What is a London dispersion force?

When an atom has an instantaneous dipole moment in another atom close by; they are present in all atoms both polar and non polar

What is a solvent?

the substance in which the solute dissolves, present in greater amount

exothermic reaction

Releases heat, ΔH is negative

endothermic reaction

energy is absorbed as heat, heat put in, ΔH is positive

Dissolving

molecules broken apart

What is a solute?

the substance that is dissolved, present in lesser amount

What is enthalpy (H)?

the heat content of a system

What is free energy (G)?

energy available to do work

When G is 0....

reaction is at equilibrium

when G is positive.....

reaction is non spontaneous (endergonic)

When G is negative....

reaction is spontaneous (exergonic)

Exergonic reaction

Energy leaving the system.

Endergonic reaction

Energy entering the system.

Standard state

1 M concentration at 298 K.

Miscible

Two liquids that mix together.

Polar and ionic compounds are more soluble in what

polar solvents

nonpolar are soluble in what

nonpolar solvents

Lattice energy

Energy holding ionic molecules together.

Heat of hydration

the energy added to overcome attractions between water molecules and energy released in forming attractions between water molecules and ions is combined

Solution equilibrium

Constant dissolution and recrystallization between molecules.

what can affect rate of solution formation?

1) state of subdivision of solute

2) degree of agitation during solution preparation

3) temp. of solution components

what are some properties of solutions?

contains 2 components, variable composition, properties change as ratio of solute to solvent is changed, dissolved solute present as individual particles, solutes remain evenly distributed (wont settle), solute can be separated from solvent by physical means

Unsaturated solution

solution with less dissolved solute than max capacity

Saturated solution

Max solute has been dissolved, adding more solute = cant be dissolved.

Supersaturated solution

Becomes unstable; crystals form above the curve.

as you increase the temp. for gases what happens to solubility

solubility decreases

Henry's law

Amount of gas that will dissolve in liquid is proportional to its partial pressure.

Molality (m)

Moles of solute per kilogram of solvent.

Molarity (M)

Moles of solute per liter of solution.

Percent by mass

Mass of solute divided by mass of solution times 100.

percent by volume

volume of solute/volume of solution x 100

Mole Fraction (X)

moles of solute or solvent/moles of solution

Colligative properties

properties that depend on the concentration/number of solute particles but not on their type

how many particles does 1 mol for nonelectrolytes equal?

1 particle

how many particles does 1 mol for electrolytes equal?

2 particles

true or false: vapor pressure above a solution is lower than vapor pressure of pure solvent

true

Raoult's Law

Psoln = Xsolv * Psolv.

freezing point depression

FP of solution is lower than that of pure solvent.

ΔTf = imKf

boiling point elevation

BP of solution is higher than that of pure solvent.

ΔTb = m*Kb

Osmosis

Solvent moves from low to high solute concentration across a semipermeable membrane.

osmotic pressure

the pressure that would have to be applied to a pure solvent to prevent it from passing into a given solution by osmosis

II=iMRT

Van't Hoff factor (i)

Moles of particles in solution divided by moles of formula units dissolved.

Hypertonic solution

Concentrated solution; water leaves the cell.

Isotonic solution

Equal concentration inside and outside the cell.

Hypotonic solution

Concentration is higher inside the cell; water enters the cell.

Dissociation

Process where solute breaks apart into ions, one (+) atom and one (-) atom dissociate

Entropy

Measure of randomness and energy dispersal.

Qualities of nonpolar molecules

more nonpolar = less soluble, symmetrical, hydrophobic, low melting and boiling points

Qualities of polar molecules

Asymmetrical, unequal electron sharing, higher melting and boiling points

isomotic solution

normal, same concentration, no net water movement

Hyperosmotic solution

water flows out, solution more concentrated

hyposmotic solution

water flows in, cell is more concentrated/has more electrolytes

what are solutions?

homogenous mixtures

What are suspensions?

Heterogeneous mixtures with large visible solutes that settle out on standing

what are colloids?

heterogenous mixtures that dont separate on standing

Hydrophilic

Attracted to water, polar

Hydrophobic

Aversion to water, nonpolar

Brownian motion

Random collision of particles.

What is a micelle and what does it do?

They are sphere shaped water-soluble micelles with polar end on outside and insoluble nonpolar end on the inside

Take up free fatty acids (oil and soap example) which are dissolved in the interior of the molecule

The Tyndall Effect

Scattering of a light beam as it passes through a colloid