Chem 122 Exam 2 study guide
Chem 122 Exam 2 study guide Chem 122
Popular in General Chemistry I
Popular in Chemistry
This 5 page Study Guide was uploaded by bklaas2 on Monday October 10, 2016. The Study Guide belongs to Chem 122 at University of Illinois at Chicago taught by Dr. Sherwin P. Montaño in Fall 2016. Since its upload, it has received 163 views. For similar materials see General Chemistry I in Chemistry at University of Illinois at Chicago.
Reviews for Chem 122 Exam 2 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: 10/10/16
Chem 122 Exam 2 study guide: Created by Brennan Klaassen Material tested on: Chapters 4(59), 5, 9(13,59), 10(15) Chapter 4: Electrolytes Electrolytes are substances that dissolve in a liquid which allow electricity to flow. Most salts are electrolytes. Sugars are generally non electrolytes. Strong electrolytes are substances that dissociate completely to allow a lot of electricity to flow. Weak electrolytes dissociate partially. Strong electrolytes can be strong acids and strong bases. Weak electrolytes are weak acids and weak bases. Full list of solubility is on 161 of text book. Precipitation Reactions: A chemical reaction where a precipitate is formed. Starting with two aqueous solutions, and when mixed together they form a solid. These solids are called insoluble. Compounds that will not dissolve or mix in water. Complete and Net Ionic Equation Complete ionic equation: each separate ion is present in a chemical reaction Net ionic equation: Shows only the ions that change during the reaction. Ex: Molecular equation: Pb(NO ) (aq3 2 2 KCl (aq) > PbCl (s) + 2K2O 3 Complete Ionic Equation: Pb (aq)+ 2 NO (aq) + 2 K (aq) + Cl (aq)> PbCl (s) + 2K (aq)+ 2NO + 3 2 3(aq) 2+ Net Ionic Equation: Pb (aq)+ Cl(aq)> PbCl (s) 2 Titration: Achieving the equivalence point. Most commonly used in AcidBase reactions (neutralization reaction) balancing an Acid and Base to achieve a neutral pH= 7. Titration can be used to find the concentration of a solution, with another known concentration of the opposite pH. Most Acid Base reactions form water and a salt. GasEvolution reactions two aqueous solutions that are mixed and form a gas. Oxidation Reduction Reactions: AKA Redox Reactions A chemical reaction where electrons are transferred from one reactant to the other. Oxidized: loss of electron(s) Reduced: gain electrons(s) Oxidizing agent: caused the other reactant to lose electron(s) Reducing Agent: caused the other reactant to gain electron(s) Oxidation state: Imaginary number assigned to each element in a compound to determine the electron flow in a chemical reaction. For full list of rules see Ch. 4 revised powerpoint slide 92,93 Redox reaction example: H + F 2 HF.2 Chapter 5: gas Gas: State of matter, where the molecules are randomly distributed, spaced evenly, and occupy all available space. Pressure units: mmHg, atm, Pa Ideal Gas Laws: STP: 1atm, 273 K, standard temperature and pressure Boyles law Charles Law Avogadros Law There is an inverse There is a proportional There is a proportional relationship between volume relationship between volume relationship between volume & pressure and temperature and mols P 1 V 1P *2V 2 V1/T1=V 2T 2 V 1n1=V 2n 2 Combine gas law: PV=nRT, where R is constant .08206(L* atm)/(mol * K) Pressure: force applied by each individual atom bouncing around its container Temperature: speed at which the molecules are moving. The larger the molecules the slower they move at STP Density of gas: Molar mass/ molar volume Also found with (P*molar mass)/(RT) Dalton's Law of partial pressures: The sum of the partial pressures of the components in a gas mixture equals the total pressure. Mole Fraction: the percentage of pressure one component applies, equals to the percentage of mol the one component applies compared to the total mol. Stoichiometry in gas: Similar to aqueous stoichiometry calculations, but use the ideal gas Law to find mols instead of mass. Have to be given Pressure, temperature, and volume, to find the mols where you can mulitply by the molar ratio given in the balanced equation, to find the number of mols, or anything else in the Ideal Gas Law equation. Temperature and kinetic energy/ velocity Basic assumptions in the Kinetic Molecular theory: 1. The size of the particles are negligibly small 2. Average Kinetic energy is proportional to the temperature in K 3. The collision of two particles is completely elastic, which means there is no loss of kinetic energy Pressure= Force/Area 2 Average kinetic energy equation: KE = ½avgogadros # * M(mass) * U (velocity) Average kinetic energy equation: 3/2* RT where R is a different gas constant 8.314 J/mol * K Diffusion: process by which gas molecules spread into a space. Diffusion of a gas is proportional to inverse of the square root of their density. Effusion: movement of gas through a small hole/ vacuum Common problem: putting a metal in an acid, and an airtight seal around a tube that goes into water,and the gas is collected above the water in a beaker. The total pressure above the water is given, and they want to know the amount in grams of hydrogen gas. Explained in text book pg 219 Chapter 9: The Lewis Model Different types of Chemical Bonds Nonmetalnonmetal= covalent bonds, shared electrons Nonmetal metal= ionic bonds, transferred electrons metalmetal= metallic bonds, clumps of electrons Valence Electrons as Dots: When drawing lewis structures, you only need to take into account the valence electrons, the easiest way to find the number of valence electrons is the periodic table. Each column has the “A” number of valence electrons. So Carbon has 4 valence electrons. You draw the dots around the symbol of the element. Start with 1 dot on each side of the symbol, and if it has more than 1, then pair them up Covalent Bonding In Lewis structures, the covalent bonds are represented by a line drawn between each symbol. One Line contains 2 electrons. If there is a double bond, then two lines are drawn parallel to each other. If it’s a triple bond, then three lines are drawn between the symbols parallel to each other. Electronegativity: The strength of an element to attract an electron. Given in a chart on page 395 Polarity: the difference of electronegativity between two elements, or more. Dipole Moment: The quantified version of Polarity. Measured in Debye. Calculated by magnitude of the charge that is shared between the two electrons, multiplied by the distance separated. Commonly shown as this equation μ=qr. A nonpolar molecule has a dipole moment vector sum of 0. A pair of nonbonded valence electrons are more electronegative than any bonded electrons, so most of the time, the molecule with nonbonded electrons in the central atoms will be polar, unless there are two pairs which balance eachother out, like a triagonal bipyramidal with 2 free pairs of electrons. If the dipole moments are completely balanced and equal the molecule will be non polar. If They are not, then it will be polar. Percent Ionic Character: measured dipole moment of the bond / dipole moment if electron were completely transferred Writing Lewis Structures: 1. Draw out each element around the center element. Draw a single bond between each element and the center. 2. Count the total number of valence electrons shared by all of the atoms in the molecule. Then subtract the electrons used in bonding. Then evenly distribute the valence electrons around the the outer atoms first, then the inside atom. Try to make as many octets as you can. 3. If they don’t have a complete octet, then try a double or triple bond instead. 4. To write the most balanced/ most stable lewis structure, you need elements with the fewest formal charges. So the most elements with formal charges of 0 or as close as possible. Formal charge= Oxidation state Exceptions H only can take 2 electrons instead of the usual octet. Be can only use 4 electrons, B is most stable with 6 electrons instead of 8. Expanded octet: On the periodic table, any element between period 48 can contain more than 8 electrons, because it starts building onto its next shell of electrons. Chapter 10 VSEPR theory: Valence shell electron pair repulsion theory Electron geometry Linear 180 Trigonal planar-120 Tetrahedral- 109.5 Trigonal bipyramidal- 5 electron groups around the central atom. Octahedral 90
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'