1 Matter, Mass, Molecules, Moles, & Motion Flashcards
Atomic Weight
Atomic mass unit (AMU) designation of weight 1 AMU = 1 / (6.02 x 10^23) g/mol 1 Mol = 6.02 x 10^23 1 AMU element = grams when 1 Mol present 1 Mol Carbon = 12g
Molecular Weight
Add atomic mass of all elements present in molecule
C6H12O6 = (6x12) + (1x12) + (16x6) = 180g
Atomic Number
Number of protons in the nucleus of an atom
Does not change - would change the element
Hydrogen 1 proton (+)
Calcium 20 protons (+)
Atomic Mass
Total number protons and neutrons in the nucleus
Nitrogen 14.007
7+ protons 7 neutrons (neutral)
Isotope
Same element (# protons) w/ different number neutrons Different atomic mass Nitrogen-15 7+ protons 8 neutrons Atomic mass = 14.007
H2O Properties
Universal solvent d/t dipole nature
Less dense when frozen - ice floats
Amphoteric - acid & base
High latent heat - stores more heat per unit volume than other substances and releases heat slowly
High vaporization heat - large amount heat required to break hydrogen bonds and the heat carried off as H2O vapor
Cohesive (molecules tend to stick together) AND adhesive (tend to stick to surfaces w/ polar groups)
Dissociates into H+ & OH¯
Attraction & repulsion forces among H2O molecules - produces space between for gas molecules
HIGH ↑BP ↑MP
Atom
Smallest fraction of an element w/ element characteristics
“Building block”
Composed of subatomic particles - protons, neutrons, electrons
Element
Substance that cannot be separated into simple substance
C, O, & N
Oxygen exists as diatomic element (O2)
Molecule
Two or more atoms chemically joined together
H2, N2, O2
Same elements
Exist in nature bound to self
Compound
Molecule that contains at least 2 different elements
C6H12O6 (glucose)
Physical Change
State of matter
Solid - less energy, densely packed, slowest
Liquid - more energy, less dense, faster
Gas - most energy, moving & dispersing, fastest
Chemical Change
Change in matter composition
Bonds broken & new bonds formed → new chemical entity produced w/ different properties/reaction
CO2 + H2O → H+ + HCO3
Gravity
Attraction b/w all objects and force r/t
Smaller distance = ↑ force
1 / d^2
Weight
Gravitational force experienced by body (mass) on earth
Relative to gravitational force applied to mass
Mass
Unchanged
↑ mass ↑ gravity reaction ↑ weight
Adhesion
Interaction b/w unlike molecules
H2O molecules attract to the glass
Pulling down & raising up along sides
CONCAVE
Cohesion
Interaction b/w like molecules Exhibit mutual attraction force ↑ distance ↓ force CONVEX Liquid pulls away from glass towards other H2O molecules
Octet Rule
1st shell 2e¯
2nd & 3rd shell 8e¯
Molecules react w/ other molecules to fill outer (valence) shell and become more stable
Covalent Bonds
Shared e¯ pair b/w 2 atoms
Overlap orbitals or e¯ clouds to satisfy octet therefore more stable
Equal = non-polar
Unequal = polar
Density
D = M / V 1Mol = 22.4L Gram molecular weight or mole Liquids measured in grams/cm^3 (cm^3 = mL) Gas/vapors: MW/GMV or g/L
Avogadro’s Number
Equal volume gas at STP have same number molecules
1Mol = 6.02 x 10^23 molecules
Specific Gravity
Liquid or gas weight of unit volume
Compared to standard volume H2O or dry air
Ratio b/w two densities
Liquid MW / H2O MW
Gas MW / Dry air MW
↓specific gravity = lower density ↓resistance
Halogens
Extremely reactive d/t out shell not filled 7e¯ valence Highly electronegative Form salts w/ Na+ Acids when combined w/ H+ F, Cl, Br, I
H2O Properties
Universal solvent d/t dipole & polar properties
Able to dissolve polar substances
High melting & boiling point
Less dense when frozen than in solid state (ice floats)
Amphoteric - acid & base properties
Water dissociates into H+ & OH¯ (contributes to acid/base balance)
Tetrahedral shape to maximize distance b/w e¯ pairs
Attractive and repulsive forces among H2O molecules - makes space b/w molecules for gas
High latent heat - stores more heat per unit volume & releases heat slowly
High vaporization heat - large amount heat required to break hydrogen bonds & heat carried off as vapor
Cohesive AND adhesive
