# G. Chem 2

 Phase Change: Solids: - maximum # of intermolecular forces- low energy- no compressibility (pressure)- fixed volume + shape Liquids: - some intermolecular forces- higher energy- very low compressibility - fixed volume + shape Gases: - few (almost none) intermol forces- highest E- compressible- vol fills container Phase Change Graph: When you add heat...1. Temp change2. Phase change* ONLY one of there can occur @ a time! q = m C Δ T q - heatm - massC - specific heat capacityT - temp(heat takes to heat kg of subst by 1 deg Co/K every subst has own C) q = n Hx q = heatn = moles (or mass)---> Hf = heat of fusion; Hv = heat of vaporization⇒ have to look @ UNITS determines n P vs. T --> phase changes - tells what state matter something going to exist @ temp - what happens through phase Δ if something stays constant P vs. T - H2O *slope changeliq form = most dense form (more dense than solid form) Ideal Gas: 1. Gas has no mass2. All collisions are elastic - (E completely conserved; no E lost)- (bounce & keep same amt of E)3. All molecules have the same E = avg energy of system Factors Affect Gases: - temp (↑Ek)- pressure (force of collision)- volume (decr free space b/w gas mol) P α 1/v P α T T α V PV = n R T R --> universal gas constant (always been the same)[*0.0821 L•atm/K•mol (more common) or 8.31 J/k•mol (unless ask for v)] T --> K *1 mol of ideal gas = 22.4 L @STP (T → 0oc/273K; P → 1 atm) other form of PV = n R T P1 V1 = P2 V2 T1 T2 Solubility: ability to dissolve solvent: does the dissolvingsolute: gets dissolvedsolution: l + s; l +l; l + g; g +g; s +s SOLUBILITY IN H2O: 1. All grp I & ammonium (NH4+) salts are SOLUBLE 2. NO3- (nitrate); ClO4- (perchlorate); C2H3O2- (acetate) are SOLUBLE 3. MLS: Hg, Pb, Ag are INSOLUBLE!!! COLLIGATIVE PROPERTIES Van't Hoff i = how many parts a substance dissociates into... CaCl2 → i = 3NaNO3 → i = 2 (b/c NO3 covalent b.)C6H12O6 → i = 1 [anything covalent b. ONLY 1 part] Boiling Pt Elevation: (salt in pasta H2O) ∆T = K i m K → boil/freeze consti → van't hoffm → molality [mol solute/ kg solvent] Freezing Pt depression: (salt trucks & icy roads) ∆ T = k i m Vapor Pressure/ Depression: [desire for Alian's brothers want to leave] "water's desire to become a vapor"(high Vp the more it wants to be vapor)∆ P = Χ P Χ → mole fraction Kinetics -- rates of rxn For rxn to occur: 1. collide2. collide w/ correct orientation3. collide w/ enough energy Kinetics -- Factors that affect rate: 1. Temp (kinetic E ∆)2. Concentration (↑=↑ # of collisions)3. Catalyst (↓ active E; enough # ↓)- (provide correct orientation ⇒ energy binding sites) - catalyst will only affect activation E ➱ affect overall rate Rate Expression: aA + bB + cC ⇔ dD + eE aA + bB + cC ⇔ dD + eE rate = k[A]x[B]y[C]z x, y, z = determined experimentally Authornapoleon ID26984 Card SetG. Chem 2 DescriptionG. Chem Class 2 Updated2010-07-16T03:05:23Z Show Answers