Chapter 6 - Matter

• substance maintains shape and volume
• rigidly packed 3-dimensional pattern
• definite shape
• definite volume
• particles packed and touching
• high density
• small compressibility
• very small thermal expansion

• substance assumes shape of its container
• flows readily
• indefinite shape
• definite volume
• particles touching and mobile
• high density
• small compressibility
• small thermal expansion

• substance maintains neither shape nor volume
• indefinite shape
• indefinite volume
• particles far apart
• low density
• large compressibility
• moderate thermal expansion
• mix spontaneously and completely through diffusion

attractive forces that hold atoms together in molecules and ions together in crystals

• metal + nonmetal
• complete transfer of valence electrons
• form crystalline solids
• high melting points
• water soluble
• can conduct electricity (electrolyte)

• valence electrons shared by 2 atoms in a compound
• single, double, triple bonds

• equal sharing of electrons
• occurs between same kind of atoms (H₂, Cl₂)

• unequal sharing of electrons
• occurs between atoms of different elements (H₂O, SO₃)

• the ability of an atom to attract shared electrons to itself in a covalent bond
• electrons are attracted toward atoms of highest electronegativity
• periodic table increases left to right, decreases top to bottom

• forces between molecules
• --dipole forces
• --hydrogen bonds
• --london dispersion forces

• polar covalent bonds
• electron pairs shared unequally
• unbalanced separate center of partial positive and negative charges
• positive end attracts negative end

• intermolecular force between electropositive H (bonded to N, O, F) and electronegative O, F, N
• strongest bond

• non polar molecules
• small transient momentary attractive forces
• weakest bond

• proportional to kelvin temp
• temp increaes, particle velocity increases
• at fixed temp, lighter particles move faster than heavier particles

• 1. gases move continuously, rapidly, randomly
• 2. particles are tiny / great distances
• 3. forces between molecules are negligible
• 4. collisions are elastic (no energy loss)
• 5. average kinetic energy of gas particles is same for all gases at same temp

• thin blanket of gases around earth
• 78% N₂, 21% O₂, 1% Ar, 4% H₂O, trace CO₂

force per unit area exerted by atmosphere

• force exerted per unit area
• pressure = force/area

• atm: atmosphere
• mm Hg: mm mercury
• torr
• Pa: pascal (SI unit of pressure)
• psi: pounds per square inch

1 atm = 760 mm Hg = 760 torr = 14.7 psi = 101,325 Pa

Pressure and volume inversely proportional at constant temp and qty of gas

P1 x V1 = P2 x V2 = constant k

Volume and temperature are linear

V^T^

Pressure and temp are linear

P^T^

Equal volumes of gases contain equal number of molecules (or atoms)

V1/n1 = V2/n2

PV = nRT

• P = pressure
• V = volume
• T = temp
• n = quanity of gas

total pressure of gas mixture = sum of partial pressures of exerted gases

P(total) = P1 + P2 + P3

• lose electron
• lose hydrogen
• gain oxygen
• increase oxidation number

• gain electrons
• gain hydrogen
• lose oxygen
• decrease oxidation number

• 1. ON of any single element is 0
• 2. ON of simple ion = charge of ion (Mg²⁺ = +2)
• 3. ON of 1A and 2A elements when in compounds is +1, +2
• 4. ON of H is always +1
• 5. ON of O is always -2
• 6. Sum of ON of all atoms in compound = 0
• 7. Sum of ON of all atoms in polyatomic ion = charge of ion