chem test 1

• surface tension (J/m²⁾
• hydrogen bonding leads to higher surface tension

cohesive forces

adhesive forces

adhesive forces are stronger than cohesive forces

viscosity

• stronger intermolecular forces
• long chain-like molecules

• high heat capacity
• high melting point
• high boiling point
• large enthalpy of vaporization
• large enthalpy of fusion
• utility as a solvent
• solid form is less dense than its liquid form
• (consequences of the very polar/hydrogen bonding nature)

the pattern of fixed particule positions is regular and the pttern is repeated throughout the solid

the particle positions are fixed but without a regular, repating pattern

for a crystalline solid, a single instance of the repeating pattern

locations occupied by particules that define the unit cell (atoms, molecules, or ions)

• each cubic unit cell is face to face adjacent to six other unit cells in a crystal lattice
• a single atom or ion at the periphery of one cell will extend into adjacent cells
• a particule located that the corner of a cubic unit cell extends equally into eight cells; each corner particule contributes 1/8th of a particle to the occupation of a given cell

• only has corner particles
• only contains one particle
• a = 2r
• 52% packing efficiency

• lies completely within the cell
• contains two particles (center particule and the eight eights of the corner particles)
• a = (4/square root of 3) x r
• 68% packing efficiency

• lies half within one cell and half within another cell
• contains 4 particules (3 "face" particles and the eight eights of the corner particle)
• also known as "ccp"
• a = (square root of 8) (r)
• r = (square root of 2) (a) / 4
• 74% packing efficiency
• same packng eficiency as hexagonal closest packing (hcp)

• the number of neighbors in contact with a given particle
• the higher the coordination number, the less empty space in the crystal

• percent of the lattice which is actually occupied by particles
• (V occupied/V total) (100)

4/3 pi r³

• held in place by intermolecular forces
• soft
• low melting points
• poor conductors of heat and electrical current

• held in place by covalent bonds
• 3-dimensions: crystal is strong (diamond)
• 2-dimensional: strong layers held weakly togther by dispersion forces (graphite)
• poor conductors of heat and electrical current

• includes a cation and an anion held in place by ionic bonds
• strong
• hard
• high melting points
• poor conductors of heat and electrical current in crystalline form
• good conductors when melted

• good conductors of heat and electical current
• strength and rigidity vary greatly

the amount of thermal energy that must be added to a 1 mole sample of a liquid at its boiling point in order to convert it to 1 mole of gas at that same temperature

the amount of thermal energy required to melt 1 mole of a solid at its melting point

• ln P₂/P₁ = -Hvap/R (1/T₂ - 1/T₁₎
• remember T must be in kelvins!