General Chemistry Sample Exam 2 and Outline Chapter 4 Stoichiometry Calc. & formulas 1 Chemical Equation Type of Reactions 2 Atomic and Molc' Wt AW, MW, FW % Composition 3 The mole 4 Empirical Formula determination Mol. Formula determination From Combustion Analysis 5 Stoichiometry problems: Molecules to moles Mass to moles Volume to moles Using the balance equation, molesa to molesb 6 Quantitative Information Calculating Limiting reagents Determining the amount of excess % yield calculations 7 Solution Composition Concentrations and Molarity Dilution Calculation 8 Properties of Solution Aqueous solution (Water) Ions in Water Molecules in Water Electrolytes: Weak electrolytes: nonelectrolytes 9 Acid / Base Titration calculations and concepts The experimental setup Acid-Base Stoichiometry 10 Ionic Equations 11. Metathesis Reaction Ppt reaction and solubility table 12 Oxidation – Reduction Electron transfer through single displacement Activity Series Chapter 5 Gaseous State 1 Units of Pressure 2 Ideal Gas Law Boyle's Law Charles Law Avogadro's Law Combined Gas Law 3 Molar mass by PV=nRT M = m/n = (m•RT)/PV 4 Dalton's Law of Partial Pressure PT=Pa + Pb + ... Collecting gas over water 5 Stoichiometry and Gas Laws 6 Kinetic Molecular Theory KE=1/2 mu2 urms = (3RT / M)1/2 Maxwell-Boltzmann Distribution profile 7 Diffusion (mixing of gas) Effusion (passage of gas through hole) 8 Real gas Van der Waal equation Conversion information: System LENGTH: VOLUME MASS Temperature English: 1 ft = 12 in 1 mile = 5280 ft 1 gal = 4 qt 1 qt = 2 pints 1 pt = 16 fl oz 1 lb = 16 oz 1 ton = 2000 lb ToF= 1.8ToC+ 32 SI- English: 2.54 cm = 1 in 1.609 km = 1 mi 0.946 L = 1 qt 3.785 L= 1 gal 29.57 mL = 1 fl oz. 453.6 g = 1 lb 28.35 g = 1 oz 1 kg = 2.205 lb ToC=(ToF! 32)1.8 Misc. info 1 mole = 6.02•1023 Density H2O: 1.0 g / ccGeneral Solubility Table: Soluble substances Insoluble substances containing - Exceptions containing - Exceptions nitrates, (NO3-) chlorate (ClO3-) perchlorate (ClO4-) Acetate (CH3COO-) None carbonate (CO32-) Phosphate (PO43-) chromate (CrO42-) Sulfides (S2-) slightly soluble Halogens (X-) X- = Cl-, Br-, I- Ag, Hg, Pb Hydroxides (OH-) Ca*, Sr, Ba, Alkali, NH4+ * marginally soluble Sulfates (SO42-) Ca, Ba, Hg, Pb Alkali & NH4+ None Soluble - dissolve, no precipitate (aq -phase) insoluble (or slightly soluble) - does not dissolve, precipitate forms. (s-phase) Gas law equations: Ideal Gas Law PV = nRT ! Denstiy(D) =m " Pn R T , m= mass ! R = 0.08206 L " atmmol " K Real Gas: vander Waal Equation ! P +a " n2V2# $ % % & ' ( ( V - n "b( )= nRT STP P = 1 atm, T = 0°C, 1 mole = 22.4 L Dalton's Law of Partial Pressure PT = Pa + Pb + Pc + ... ! PT= (na+nb+nc+...)R• TVT . Pa = χa • PT Pb = χb • PT . χa = na / nT χb = nb / nT Speed of Gas particles ! KE = 12mu2 ! urms=3RTM ! R = 8.314 Jmol " K Graham's Law of effusion ! ratearateb=timebtimea=MbMa Calorimetry qp = ΔH = m Cs ΔT where ΔT = Tf - Ti, Cs (H2O) = 4.184 J/g•K _________________________________________________________________________________________________________1 Combustion of a sulfide of bismuth compound, BixSy (50.00g) in O2 produced 45.30 g of dibismuth trioxide (Bi2O3). i) What are the IUPAC compound name, empirical formula and the formula weight of the bismuth sulfide (BixSy) compound? ii) What is the oxidation state of the sulfur and the bismuth in this compound? iii) Suppose in your combustion experiment, the BixSy compound also contained some bismuth oxide impurities, how would this affect the x-value in the empirical formula of BixSy (higher or lower and state your reason)? iv) Suppose instead of producing 45.30 g dibismuth trioxide in the final product of the combustion, 45.30 g of dibismuth pentaoxide is produced instead, how would this affect the y-value in the empirical formula of BixSy ? 2 Balance the following equations. i) ___KOH(aq) + ___H2SO4(aq) → ___ K2SO4(aq) + ___H2O (aq) ii) ___C4H14(l) + ____O2(g) → ___CO2(g) + ____ H2O(l) iii) N2H4(l) + ___O2(g) → ___ NO2 (g) + ___ H2O (g) iv) ___K2CO3 (aq) + ___H3PO4(aq) → ___ K3PO4 (aq) + ___CO2(g) + ____ H2O(l) v) Arsenic(III)oxide + Hydrochloric acid → Arsenic(III)chloride + Dihydrogen monoxide vi) Phosphorus + Bromine → Phosphorus tribromide vii) Calcium carbonate decomposes to calcium oxide and carbon dioxide viii) Copper(II)sulfate pentahydrate is dehydrated to ______ + ______ Identify the type of reaction above. 3 A compound of Ca, C, N, and S was subjected to quantitative analysis and formula mass determination, and the following data were obtained. A 0.250 g sample was mixed with Na2CO3 to convert all of the Ca to 0.160 g of CaCO3. A 0.0268 g sample of the compound was carried through a series of reactions until all of the S was changed to 0.0802 g of BaSO4. A 0.712g sample was processed to liberate all of its N as NH3, and 0.155 g NH3 was obtained. The formula mass was found to be 156 g/mol. Determine the empirical and molecular formulas of this compound. 4 2,4,6-Trinitrotoluene (TNT), C7H5N3O6 , can be prepared by the following two step synthesis: C6H6 + CH4 → C7H8 + H2 2 C7H8 + 6 NO2 → 2 C7H5N3O6 + 3 H2 If each step in this synthesis gives a 50% yield, how much C7H5N3O6 (TNT) in grams can be produced starting with 780 g of benzene (C6H6) ?5 Ethyl alcohol (booze), C2H5OH, also called grain alcohol, can be made by the fermentation of glucose, C6H12O6, which often comes from starch in grain: ___ C6H12O6(aq) → ___ C2H5OH(l) + ___ 2CO2(g) Determine the maximum mass (theoretical yield) of ethyl alcohol, which could be produced, from 750 g of glucose. If 150 L of CO2 is collected after the fermentation, what is the % yield. Density of CO2 (g) is 1.96 g/ L. 6 Determine which of the following will dissolve in water, then classify these as (s) strong electrolyte, (w) weak electrolyte or (n) non-electrolyte. i) NH3 ii) PbSO4 iii) KHSO4 iv) Hg2Cl2 v) HNO3 vi) NH4OH vii) C2H5OH Explain your answer 7 Write the net ionic equation for any reaction that occurs upon mixing each pair of solution: i) silver nitrate and barium chloride ii) Magnesium sulfate and