States of Matter Their Nature & Behavior

Assumption #1: Assumption #1: Small particles with mass Explains increase in mass of inflated ball Assumption #2: Assumption #2: Particles separated by large distances Explains compressibility & low density Assumption #3: Assumption #3: Particles in constant, rapid motion Explains filling container ELASTICParticles perfectly ELASTIC so no kinetic energy lost in collisions

1.Gas consists of very small particles each with mass 2.Distance separating gas particles is large 3.Gas particles in constant, rapid, random motion 4.Collisions are random & perfectly elastic 5.Average kinetic energy of particles depends on temperature 6.Gas particles exert no force on one another

Based on 4 factors: 1.Amount of gas (n) 2.Volume (V) 3.Temperature (T) Measured in degrees Kelvin ( o K)Measured in degrees Kelvin ( o K) 4.Pressure (P) Measured in atmospheres (atm) or millimeters of Mercury (mm Hg)Measured in atmospheres (atm) or millimeters of Mercury (mm Hg) STP = 273 o K and 1atm or 760mm Hg

Boyle’s Law (Pressure & Volume) Pressure & Volume are inversely proportional to each other As one goes up, the other goes down P 1 V 1 =P 2 V 2

Charles’s Law (Temperature & Volume) Temperature & volume are directly proportional to each other As one goes up, so does the other V 1 T 2 =V 2 T 1

Avogadro’s Law (Volume & Particle #) Equal volumes of gases at same temp & pressure have equal # of particles Dalton’s Law (Partial Pressures) Sum of partial pressures is equal to total pressure of a gas mixture

IDEAL GAS LAW PV = nRT

State of room temp depends on strength of attraction between particles Solids – STRONG Liquids – Medium Gas – WEAK or nonexistent Intermolecular forces Inter = between Intermolecular forces – between molecules Intra = within Intramolecular forces – ionic & covalent bonds

Dispersion Force Attraction between induced dipolesAttraction between induced dipoles (temporary changes from spherical shape of an atom can produce temporary dipole which then induces one nearby into a temporary dipole) Boiling points of liquids measures strength of dispersion forceBoiling points of liquids measures strength of dispersion force Gets larger as atomic mass increasesGets larger as atomic mass increases

Dipole-Dipole Forces Formed between polar molecules with permanent dipolesFormed between polar molecules with permanent dipoles Hydrogen Bonding Strong intermolecular forceStrong intermolecular force Formed between polar molecules where covalent bonds exist between H and F,O or N which have high electronegativities.Formed between polar molecules where covalent bonds exist between H and F,O or N which have high electronegativities. Ex: WaterEx: Water

Viscosity Friction or resistance to motion of molecules moving past one another Stronger IMF’s = more viscosity Increases as temperature decreases “Slow as molasses in January…”

Surface Tension Imbalance of surface making it behave solid-like Strong for water

Specific Heat Amount of heat absorbed or lost for 1g of substance to change 1 o C Water has high specific heat – it resists temperature change Keeps earth within viable temperature limits.

Density of Ice Solid water is less dense than its liquid because as hydrogen bonds freeze, they force molecules further apart In large bodies of water, top layer of ice actually insulates water below 4 o C is water at its most dense

Universal Solvent Water dissolves many materials creating aqueous solutions (water is solvent, what’s being dissolved is solute) This property is the direct result of water’s polar structure HydrophilicHydrophilic – substances attracted to water HydrophobicHydrophobic – repel water (or not attracted)

Organisms rely on water’s high heat of vaporization to remove body heat High Heat of Vaporization

Evaporative Cooling AP Photo/Darin Cummings

Nature of Solids Crystalline Molecules in highly ordered, repeating pattern Ex: salt, sugar, gemstones, snow Amorphous Appear solid but are not crystalline Behave as supercooled liquids Ex: glass, rubber, wax

Properties of Solids Physical Properties, such as Electrical conductivity Melting point Hardness depend on Types of particles Strengths of attractive forces between particles

Types of Solids Metallic Excellent electrical & thermal conductors Ex: Al, Cu, Ag, Fe Molecular Lower melting point; poor conductors Ex: Organic compounds, water, carbon dioxide Ionic Brittle; high melting point; poor conductors Ex: Typical salts, NaCl Covalent Network High melting points Ex: diamond form of carbon

Solutions Types of Solutions 1.Solid Metal alloys 2.Gaseous Air 3.Liquid Aqueous solution

Concentration of Solutions amount of solute in a given amount of solvent Molarity – number of moles per liter Molarity = Moles of solute L of solution

Acids & Bases In pure water, the concentration of H + and OH - ions is equal When acids or bases are added to water, these concentrations change quickly pH is a measure of hydrogen ion concentration on a scale between 0-14

10 –1 H + Ion Concentration Examples of Solutions Stomach acid, Lemon juice 1 pH 10 0 Hydrochloric acid0 10 – –3 Vinegar, cola, beer 3 10 –4 Tomatoes 4 10 –5 Black coffee, Rainwater 5 10 –6 Urine, Saliva 6 10 –7 Pure water, Blood 7 10 –8 Seawater 8 10 –9 Baking soda 9 10 –10 Great Salt Lake –11 Household ammonia –12 Household bleach –13 Oven cleaner –14 Sodium hydroxide14

Acids Chemical compounds that donate H+ ions as they dissociate in solution (Bronsted- Lowry definition) EX: HCl  H+ Cl- The more acidic a solution, The higher the H+ concentration The lower the pH Taste sour pH < 7

Bases Compounds that accept H+ ions and remove them from solution (Bronsted- Lowry definition) Some donate OH- ions The more basic a solution, The lower its H+ concentration The higher its pH value Taste bitter community.tvguide.com

Buffers Substances that resist changes in pH Many of these in the body since even minor changes can be life threatening EX: blood ph is 7.4 CO 2 (carbonic acid when dissolved in water) donates H + to lower pH HCO 3 (bicarbonate) binds excess H + to raise pH I am H 2 O I am H 2 O

Neutralization When bases and acids of similar strength are combined, the pH of the solution will approach neutral (pH 7) Water is often a product of a neutralization reaction.