Chem032 Exam 1 Study Guide
Chem032 Exam 1 Study Guide Chem 032
Popular in General Chemistry 2
Popular in Chemistry
verified elite notetaker
This 6 page Study Guide was uploaded by Lindsey Koski on Friday February 5, 2016. The Study Guide belongs to Chem 032 at University of Vermont taught by Professor Ruggles in Spring 2016. Since its upload, it has received 33 views. For similar materials see General Chemistry 2 in Chemistry at University of Vermont.
Reviews for Chem032 Exam 1 Study Guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/05/16
CHEM032 EXAM 1 STUDY GUIDE CHAPTER 12 – SOLUTIONS Solute – species dissolved Solvent – does/causes dissolving Forces: Solute/solvent forces > solute/solute forces, solvent/solvent forces -Forces of Attraction Electrostatic forces o Strong o Ionic bonds o Ex.) NaCl Large molecules (greater than Network Covalent Forces o Strong 500g/mol) o Ex.) C3 (C2 O1000H 3 strncreaosFOA Hydrogen Bonding o –OH group o –NH group o –CO 2 group o –HF small molecules Dipole/Dipole forces (less than o Comes from permanent dipole 500g/mol) o Polar molecules Dispersion Forces o No permanent dipole o Non-polar molecules Dissolution o Weaker FOA = faster dissolution Larger charge = stronger FOA o If same charge, smaller radius = stronger FOA (smaller ions) Predicting solubility “like dissolves like” = match the FOA -solute: solid, liquid, or gas - solvent: always liquid Prediction rules 1.) Generally a liquid solute is more soluble than a solid or gas solute 2.) Liquid vs. liquid solutes a. Identify solvent’s FOA i. Dipole/dipole: polar ii. Dispersion: non-polar iii. H-bonding b. Identify solute’s FOA i. Solutes with H-bonding are soluble in H-bonding solvents (ex: water) ii. Solutes without H-bonding → molecular solvent Molecular solvent: Polar: CH 2l 2 CHCl 3 Non-polar: CH (CH ) CH , CCl 3 2 4 3 4 iii. Exceptions 1. Ex: CH C3 CH2CH 2O H2– h2s H-bonding a. BUT: once a molecule exceeds 4 carbons, water solubility decreases i. Molecular solvent then preferred 3.) Solid vs. solid solutes a. Weaker forces in solid solute = increased solubility b. Ionic: water as a solvent c. Covalent: molecular solvent 4.) Gas vs. gas solutes a. Stronger forces in gas = increased solubility Vocabulary Miscible- homogeneous solution (mixed) Non-miscible – heterogeneous solution (not mixed) Suspension – solute not completely dissolved (it is suspended); solid distributed throughout (not localized at bottom); ex: fog, smoke, milk, foam Non-saturated – more solute can dissolve Saturated – completely dissolved; no more solid can dissolve (at room temp) Super-saturated – past the point of saturation (due to increase in temp) Dilute – contains small concentration of solute Concentrated – contains large concentration of solute % volume = (Volume solute / volume solution) x 100 % mass = (mass solute / mass solution) x 100 Ppt = parts per thousand x Ppm = parts per million (mass solute / mass solution) x 10 Ppb = parts per billion Molarity: M = (moles solute / Liters solution) Molality: m = (moles solute / kg solvent) Gas solutes Henry’s Law Sgas = KH gas increase P = increase S Sgas= solubility of gas (M, mol/L) KH= Henry’s constant (mol/Latm) Pgas= pressure (atm) Liquid Solutes Raoult’s Law P soln X liq1ᵒ liq1 X liq2ᵒliq2 Psoln= Vapor pressure of solution *when vapor pressure = atmospheric pressure….boiling occurs X = mol fraction Pᵒ = pure vapor pressure Solid Solutes 1.) ΔH soln= ΔH solute ΔH solvent+ ΔH mix ΔH soln + endothermic, - exothermic ΔH soluteΔHsolventalways + (because forces are breaking) ΔH mixlways – ΔH soln= -ΔH latticeΔH hydration ΔH = ΔH + ΔH hydration solvent mix 2.) Van’t Hoff Factor (i) Molecular solute: i=1 (1 mol solid solute = 1 mol dissolved solute) Ionic solute: i≠1 (i>1) (1 mol solid solute ≠ 1 mol dissolved solute) i predicted: sum of coefficients of products i predicted ≠ i observed (i obs / i pred) x 100 = % ionized 3.) Vapor Pressure Lowering P soln X solvent solvent Remember to multiply mols solute (in the mole fraction) by i* If Pᵒ is not given, use: ΔP =soluteᵒsolvent 4.) Boiling point elevation ΔT = ik b ΔT: always + Kb: molal boiling point constant (kgᵒC/mol) m: molality *always raises boiling point (compared to BP of pure solvent) 5.) Freezing point depression ΔT = ikfm ΔT: always + Kf molal freezing point constant *always lowers freezing point 6.) Osmotic Pressure Π = iMRT M: molarity R: gas law constant (0.0821 Latm/molK) T: temp (K) Π: the force required to stop the flow of liquid from high VP to low VP Chapter 13 – Chemical Kinetics: Rates of Reaction Rate = (Δ[substance] / Δt) [ ] = concentration (M, atm) For rates to be equal 1.) Apply a “-“ sign to starting materials 2.) Stoichiometry a. Put 1/coefficient in front of rate Average Rates and Reaction Order (mechanism) -Reaction order is how dependent a starting material is to the rate of reaction m Rate = k [A] k = rate constant [ ] = concentration of SM m = rxn order (with respect to A) avg rates are: - always in terms of SM - always have “k” (unit depends on SM – changes) -always have order (m&n): individual order (m or n), over order (sum of m+n) 1.) zero order rxn (m = 0): no change in rate 2.) 1 order rxn (m = 1): rate inc with linear relationship 3.) 2 order rxn (m = 2): rate inc with exponential relationship How to find k/rxn order 1.) Determine rxn order for both A and B 2.) Determine overall order of rxn 3.) Determine rate constant, k m n Rate 2 k  [B2 2 *plug in given values from data, solve for m or n, create Rate 1 k  [B1m 1n rate expression, solve for k Integrated Rate Laws To find [ ] at any given time Zero order: [A] = -kt + [A] t 0 Half life: 1/2 = [A]0/ 2k First order: *radiocativity Half-life: the time it takes for half of the original amount of ln[A] t -kt = ln[A] 0 starting material to disappear half life: 1/2= 0.693 / k or decay second order: (1 / [A]t) = kt + (t/[A]0) half life: 1/2= (1 / k[A] 0 Activation energy: the energy required to start a rxn ln(k2/k 1 = -Ea/R (1/T –21/T ) 1 Clausius-Clapeyron Eqn
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'