Exam One Flashcards by Carissa Garcia

As the molecules of a gas attract each other into a liquid and then become fixed in a solid, the system is […] energy. This is an […] change.

loses; exothermic

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Overcome the attractive forces that keep the particles fixed in place in a solid or near each other in a liquid. The system must […] energy. This is an […] change.

absorbs; endothermic

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Melting or […]. The enthalpy change is […]. For freezing the enthalpy change is […].

fusion; positive; negative

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Gas formation or […]. The enthalpy change is […]. For condensation, the enthalpy change is […].

vaporization; positive; negative

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Sublimation:

solid goes to a gas

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Sublimation calculation of enthalpy change:

heats of fusion + heats of vaporization

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Deposition:

gas goes to solid

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Deposition calculation of enthalpy change:

(-) heats of fusion + (-) heats of vaporization

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Molecules with weaker IMF are held […] tightly at the surface and vaporize more […]. Weaker IMFs are, the […] the vapor pressure.

less; easily; higher

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Vapor pressure and temperature can be converted to a linear relationship with the use of…

Clausius-Clapeyron

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Clausius-Clapeyron Equation at one at two known temperatures:

lnP = (-Hvap/R) (1/T) + C

ln(P2/P1) = (-Hvap/R) (1/T2-1/T1)

R = 8.314 J/mol*K

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% By Mass Equation:

mass of solute/ mass of solution

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% By Volume Equation:

volume of solute/ volume of solution

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Molality Equation:

amount of solute/ mass of solvent (kg)

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Molarity Equation:

amount of solute/ volume of solution

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Mole Fraction:

amount (mole of solute)/ amount of solution (mole solute + mole of solvent)

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Regions of the phase diagram represent…

conditions of pressure and temperature at which the phase is stable

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Solid-liquid line has a slightly positive slope because…

the solid is more dense than the liquid (except water)

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The triple pint of a phase diagram where…

all three phases are in equilibrium (simultaneous work)

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Critical point:

two densities become equal and the phase boundary disappears

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How does the phase diagram for water differ?

the solid-liquid line has a negative slop because the solid form is less dense

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How does the phase diagram for water differ?

the solid-liquid line has a negative slop because the solid form is less dense

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List the 3 bonding forces:

ionic
covalent
metallic

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List the 6 IMF forces:

ion-dipole (NaH2O)

H-bond (H to N, O, F)

ion-induced dipole (FeO2)

dipole-dipole (ICl-ICl)

dipole-induced dipole (HCl-ClCl)

dispersion (F2-F2)

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Ion-Dipole forces: The prime example would be... Why does this occur?

any ionic compound dissolving in water the attraction between the negative pole and ion is greater than the between the ions themselves

If the dipole-dipole forces of 2 compounds have a similar mass, what can determine the stronger force?

the one with the greater dipole moment

For a NP molecule, distortion of an electron cloud induces a [...].

temporary dipole moment

For a P molecule, distortion of an electron cloud induces an [...].

increase in the already existing dipole moment

Polarizability:

how easily the electron cloud of an atom can be distorted

Which is more polarizable: smaller particles or larger ones?

larger; smaller molecules are held more closely to the nucleus

List the 2 trends of the PT when it comes to polarizability:

1. increases down a group (atomic size increases and larger electron clouds are easier to distort) 2. decreases across a period (increasing Zeff makes the atoms smaller and hold the electrons more tightly)

Cations are [...] polarizable than their parent atoms because they are smaller. Anions are [...] polarizable because they are larger.

less; more

When an ion distorts the electron cloud of a NP substance what forces result?

an ion-induced dipole

When a P molecule causes the distortion to an NP electron cloud what forces result?

a dipole-induced dipole

London dispersion occurs between all particles because they result from...

the motion of electrons

Dispersions are also known as...

instantaneous dipole-induced dipole forces

How can a dipole be formed in a dispersion electron cloud?

instantaneously there's more electrons on one side of the nucleus than the other

The relative strength of dispersion forces depends on the [...] of the particles.

polarizability

A linear chain of carbons vs a tetrahedral shape. If the two have equal mass which has the higher bp?

chain because there are more points at which dispersion forces act

IMF: Ion + P =

ion-dipole forces

IMF: Ion + NP =

ion-induced dipole forces

IMF: P + NP =

dipole-induced dipole forces

IMF: P + P =

dipole -dipole forces

How to determine which compound has the highest vapor pressure? Why is this the case?

the one with the strongest IMF has the lower vapor pressure substances with stronger IMF mean fewer molecules will have enough kinetic energy to escape at a given temperature

We can divide solids into two broad categories:

1. crystalline | 2. amorphous

Crystalline solids:

well defined shapes because their particles occur in an orderly arrangement

Amorphous solids:

poorly defined shapes because of the lack of orderly arrangement

Unit cell:

the smallest portion of a crystal that, if repeated in all three directions, yields the crystal

Coordination number:

in a crystal, the number of nearest neighbors surrounding a particle in a complex ion, the number of ligand atoms bonded to the central metal ion

List the three types of cubic cell units:

1. simple 2. body centered 3. face centered

The coordination of each cubic cell unit:

6 for simple 8 for body-centered 12 for face-centered

How many particles make up a simple cubic? Explain with the formula.

1 (8 corners) x (1/8 particle shared between adj cells) = 1

How many particles make up a body-centered cubic? Explain with the formula.

2 (8 corners) x (1/8 particle shared between adj cells) = 1 + 1 particle in the center = 2

How many particles make up a face-centered cubic? Explain with the formula.

4 (8 corners) x (1/8 particle shared between adj cells) = 1 + (1/2 particle shared at the face) x (6 faces) = 4

Atomic solids/ noble gases crystallize in a [...].

cubic closest packing (face-centered cubic unit cell)

Molecular solids have molecules at the lattice points and often adopt [...].

cubic closest packing

Ionic solids crystallize with one ion filling hold in the [...] array of the other.

cubic closest packing

Most metals have a [...].

closest packed structure

What are some examples of amorphous solids?

charcoal, rubber, glass

Why can't amorphous solids remain ordered?

the chains of atoms cannot orient themselves quickly enough so they solidify in a distorted jumble of misaligned rows and gaps

Atomic physical properties (3)

1. soft 2. very low mp 3. poor conductor

Substances with strong IMF have a [...] vapor pressure and are less [...].

lower; volatile

Molecular physical properties (3):

1. fairly soft 2. low-mod mp 3. poor conductor

Ionic physical properties (3):

1. hard and brittle 2. high mp 3. good conductor (molten)

Metallic physical properties (3):

1. soft to hard 2. low-high mp 3. excellent conductor

Network covalent physical properties (3):

1. very hard 2. very high mp 3. poor conductor

Examples of hexagonal packing:

Mg, Ti, Zn

Example of cubic closest:

Ni, Cu, Pb, CO2, CH4, noble gases

Solvent:

substance in which other substances dissolve; the most abundant component

Solute:

substance that dissolves in a solvent

Solubility:

maximum amount that dissolves in a fixed quantity of a given solvent at a given temperature

Miscible:

soluble at any proportion

Liquids that do not dissolve each other are [...].

immiscible

Solubility of alcohols in water: when is it too low that the mixture is insoluble?

when alcohols larger than three carbons solubility decreases; insoluble at 6 or more

What is polar?

the uneven distribution of electron density

What does it mean to be polar?

to have a separation of charge leading to a molecule or compound electrical dipole moments