Chemistry 115 Final Exam Questions with Verified Solutions

Chemistry 115 Final Exam Questions with Verified Solutions Any ionic compound containing group IA or NH4+ cations are.... Always Soluble Ionic compounds containing NO3-, NO2-, ClO3-, ClO4-, C2H3O2-, & HCO3- anions are Always Soluble Ionic compounds containing Cl-, Br-, & I- anions are soluble EXCEPT when combined with... Ag, Hg, and Pb cations Ionic compound containing SO4^2- are soluble EXCEPT when combined with... Ag, Hg, Pb, Ca, Sr, Ba Ionic compounds containing So3^2-, S^2-, CO3^2-, PO4^3-, CrO4^2-, & CrO7^2-. anions are insoluble EXCEPT when combined with.... Group 1A or NH4+ anions Ionic compounds containing O2- and OH- anions are INSOLUBLE except when combined with... group IA, NH4+, Ca, Sr, Ba Chemistry A science studying matters and their changes Matter Anything that takes up space and has mass Physical change Changes that occur without changing the objects chemical make up. Example: water turning to ice Chemical change Changes that occur with modification of chemical make up of substance, new stuff is made. Example: Rust Intensive Property Properties independent of the size of the sample. Examples: Temperature, density. Extensive Property Properties depends on the size of the sample. Example: Mass, volume, energy Pure Substance Substance that has fixed composition and a unique set of properties. Can be elements, or compounds. Mixture Contains two or more pure substances Homogeneous Mixture uniform mixture with same composition throughout Heterogeneous Mixture Mixtures with various composition. Example: salt and sugar mixture, can be picked apart Exact Number Value is exactly known, a counting definition, and has no error/uncertainty Measured Numbers numbers without exactly known value due to measuring process or device. Some error/uncertainty present. 0 significance 0 before first nonzero digit is never significant. 0 between nonzero digits ALWAYS significant 0 after last nonzero digit depends on decimal point Law of Mass Conservation No detectable gain or loss of mass occurs in chemical reactions, mass is conserved Law of Definite Proportion In a given chemical compound, the elements always combine in the same proportion of mass Dalton's Atomic Theory Elements consist of tiny particles called atoms. Each elements is characterized by mass of its atoms. Compounds are formed when atoms of two or more elements combine in a whole # ratio. (law of definite proportion) Chemical reactions only rearrange atoms, no atoms will disappear or change into other atoms. (law of mass conservation) JJ Thompson Experiment Used a cathode anode ray tube. Discovered negatively charged particle (electron) Milliken's Oil Droplet Experiment discovered the charge of the electron by using a beam of electrons (x-ray) and falling oil droplets. The oil droplets floated due to repulsion of the negatively charged electrons. Rutherford's Alpha Particle Experiment This experiment discovered the nucleus of the atom. Main group elements Representative elements/ Group A. First 2 columns and last 6 columns Molecular Compound combinations of 2 or more nonmetals, consist of discrete molecules that move about as a unit, smallest bit referred to as a molecule, chemical formula is called molecular formula, atoms held together by covalent bond. Ionic Compound Formed by combination of cation (+) and anion (-). Consist of 3-D array of ions, no particular cation belongs to a particular anion Smallest bit is called a formula unit. Ions held together by ionic bonds NH4+ ammonium OH- hydroxide NO3- Nitrate NO2- Nitrite HCO3- Bicarbonate CO3 2- Carbonate SO4 2- Sulfate SO3 2- Sulfite PO4 3- Phosphate Naming Ionic Compounds Metal cation & anion: Metal name + root + ide Example: FeCl2 Iron (II) Chloride Naming Molecular Compounds # prefix and first element name + # prefix+root+ide Example: CO2 carbon dioxide H2O dihydrogen monoxide Naming Binary Acids (H+nonmetal element) Hydro+Root+ic acid Example: Hydrochloric Acid Naming Oxyacids (H+X+O) Per, ic, ous, hypo Example: HClO4 Perchloric Acid HClO3 Chloric Acid HClO2 Chlorous Acid HClO Hypochlorous Acid Isotopes Same protons, different neutrons Isotope Abundance and Average Mass [(amu)(percent decimal)] + [(amu)(percent decimal)]= Average Atomic Mass Percent Yield actual yield/theoretical yield x 100% Nonelectrolyte Not charged, Molecular compounds Example: C12H22O11 sugar Electrolyte (aqueous sol'n conducts electricity) Strong and weak electrolytes Strong Electrolytes dissociates 100% into ions Soluble salts: any ionic compound except hydroxides Strong bases: Li, na, K, Rb, Cs, Ca, Ba, Sr (OH) Strong acids: HCl, HBr, HI, HNO3, HCl3, HCl4, H2SO4 Weak Electrolytes < 100% dissociation weak acids: HF, H2S, HNO2, H2CO3, H2SO3, HClO, HClO2, HC2H3O2... Weak base: NH3 ammonium Molarity Mole of solute/L of Sol'n Dilution M1V1=M2V2 Titration adding base to acid or acid to base to achieve neutralization Neutralization MH+ x VH+ + MOH- x VOH- Oxidation-Reduction Reaction OILRIG oxidation involves losing e- Reduction involves gaining e- Whatever is oxidized is the reducing agent Whatever is reduced is the oxidizing agent Oxidation Numbers #s used to track electron gaining/losing during redox reactions How to Balance a Redox Reaction (Acidic) Split into half rxn Balance all elements except H & O Add water to balance O Add H+ to balance H Balance charge with e- Combine half reactions to cancel e- Inventory check of Elements and charge How to Balance a Redox Reaction (Basic) Split into half rxn Balance all elements except H & O Add water to balance Add H+ to balance H Add OH- to neutralize H+ Balance e- Combine half reactions Cancel out e- and OH- H+ that can combine Inventory Check Activity Series Single replacement redox rxns Cs is the most active in metal, can replace all. F2 is the most active in non metal. F2>Cl2>Br2>I2 q > 0 absorbed heat. Endothermic. K.E. up & Temp up q < 0 released heat. exothermic. K.E. down & Temp down J = Joules unit of heat Kgxm^2/s^2 1 cal = 4.184 J Heat Capacity (C) amount of heat to raise the T of an object by 1 degree C. Extensive Property. J/C or cal/C Specific heat capacity (Cp) amount of heat to raise the T of 1 g of a substance by 1 degree C. Intensive property. J/g'C Molar Heat Capacity (Cm) amount of heat to raise the T of 1 mol of a substance by 1'C. J/mol'C and cal/mol'C 3 thermochemistry equations q=CdeltaT q= mCpdeltaT q= nCmdeltaT Isolated System/Insulated System a system that cannot exchange matter or energy with it's surroundings. "figurative box that stops matter or energy transfer with the outside world" qloss + qgain = 0 eqn to use for chemical rxn problems in thermochemistry q + deltaH = 0 Hess Law Overall Delta H of a rxn is equal to the sum of all delta H of its individual steps Standard Heat of Formation (deltaH'f) total deltaHf of products - total deltaHf of reactants Wavelength lamda. distance between 2 successive waves Frequency nu. # of peaks passing by a fixed point per unit of time. wavelength and frequency are.... inversely proportional to each other Speed of Light c= 3.00x10^8 m/s c= lamda(wavelength) x nu (frequency) Energy = h(plancks constant)x nu (frequency) or hx(c/lamda)