AP Chemistry Unit 11Denise DeMartino AP Chemistry --Unit 1 In Class Problems 1.Figure I shows a glass cylinder containing four liquids each of different density.Two of the liquids have been identified.A table containing a list of substances and their density (at 25 C) has been provided.From the list select a substance for Liquid #1 and Liquid #3.Briefly explain the reason(s) for your selections and for the remaining substances the reason they were not selected. SubstanceDensity (gmL) Mercury13.5 Water1.0 Hexane0.660 Ethyl alcohol0.789 Dichloromethane1.33 Aluminum2.699 Bromine2.928 Gold19.3 2a.Compare and contrast accuracy and precision. b)Which set(s) of measurements are precise? c)Which set(s) of measurements are accurate? d)Which set(s) of measurements are both precise and accurate? 3a.Explain the difference between an exact number and an inexact number. b)For each case, indicate whether the result is an exact or inexact number. (i)The number of faces: (ii)The mass of six apples(iii)The number of seeds in the apples in (a)(iv)The number of feet in one mile(v)The number of liters in five quarts AP Chemistry Unit 12Denise DeMartino 4.Complete the following calculations and record the result using the correct number of significant figures. Answer to correct number Calculationof significant figures 0.347 0.0732 23.436 + 82.2 (8.25 x 0.14) 0.83412.45 (6.536 6.476)99.003 + 2.0915.The density of concentrated sulfuric acid is 1.84 g/mL.Concentrated sulfuric acid is 95 % pure sulfuric acid.What volume of concentrated sulfuric acid contains 100 g of pure sulfuric acid? 6.For each of the separation techniques listed below, give an example of how the technique is used to separate the components of a mixture. a)Decantationb)Filtration AP Chemistry Unit 13Denise DeMartino c)Evaporation d)Distillation e)Paper chromatography f)Liquid-solid chromatography AP Chemistry Unit 14Denise DeMartino AP Chemistry Unit 15Denise DeMartino 7.Each diagram (A - P) show a sample of substances as viewed at the atomic level.Characterize the contents of the container in terms of each of the following categories: Category I.Homogeneous mixture, heterogeneous mixture or pure substance Category II.Element(s), compound(s) or both Category III.Solid, liquid, gas or combination of phases AP Chemistry Unit 16Denise DeMartino 8.Determine the number of kilograms in 115 pounds using 2 unit conversion factors. 9.The approximate volume of water contained in the oceans of the world is 3.3 x 108 mi3.Determine the volume in km3. 10.Given the following elements determine the number of electrons, protons and neutrons. a) 10947Ag b) 2412Mg c) 2413Al d) 10747Ag+ AP Chemistry Unit 17Denise DeMartino 11.a) Do the elements in the alkali metals group, the alkaline earth metals group and the additional metals aluminum and gallium form positive or negative ions?What is the normal ionic charge for each group? b)Do the elements in the halogen group, and the element oxygen form positive or negative ions (primarily)?What is the normal ionic charge for each group? 12.NaCl CaBr2 K2SCu3N2 NOSO3 NO2 P4O10 N2O4 NF3 ___________ 13.Many familiar substances have common, unsystematic names.In each of the following cases, give the correct systematic name: a)saltpeter (KNO3)__________________ b)soda ash (Na2Co3)__________________ c)lime (CaO)__________________ d)baking soda (NaHCO3)__________________ e)lye (NaOH)__________________ f)muriatic acid (HCl)__________________ g)milk of magnesia (Mg(OH)2)__________________ h)dry ice (CO2)__________________ i)ammonia (NH3)__________________ 14.Write the chemical formula of each substance mentioned in the following word descriptions. a)Zinc carbonate can be heated to form zinc oxide and carbon dioxide. b)On treatment with hydrofloric acid, silicon dioxide forms silicon tetrafluoride and water. c)Sulfur dioxide reacts with water to form sulfurous acid. d)The substance hydrogen phosphide is commonly called phosphine. e)Perchloric acid reacts with cadmium to form cadmium (II) perchlorate. f)Vanadium (III) bromide is a colored solid. AP Chemistry Unit 18Denise DeMartino 15)Practice naming compounds given their formula and writing the formula of a compound given its name. 16.NH4NO3NaCN KNO2BaSO4 Ca(ClO4)2 Hg2O CuCO3 NaHCO3 17. HCl (g)HClO HCl (aq)H2SO4 HClO4 H2SO3 H2CO3 H3PO4 18.Complete the following table M, Molarm, Mass ofn, Moles ofN, Number of atoms,FormulaMass gmolsample (g)sample (mol)molecules, or formula units H2SO4 98.00.825 Cr2O39.63 x 1023 unknown56.80.476 Mo62.8 AP Chemistry Unit 19Denise DeMartino 19.IsotopeRelative MassPer Cent Abundance 20Ne19.992 u 90.92 21Ne20.994 u2.57 22Ne21.991 u8.82 Find the avg atomic mass! 20.Two isotopes of chlorine exist in nature.75.77% of chlorine is 35Cl with a mass of 34.96885 amu. What is the mass of the other isotope of chlorine? 21.Determine the percent composition of each element in Ni3(PO4)2. AP Chemistry Unit 110Denise DeMartino 22. Determine the empirical formula for a compound which is 26.6 % potassium, 35.4 % chromium and 38.1 % oxygen.The compound has a molecular weight of 294.2 g/mol.What is the molecular formula? 23.Determine the amount of iodine produced when 145 g of KI react with excess copper (II) chloride. 2CuCl2(s) + 4KI(s) 2CuI(s) + 4KCl(s) + I2(s) 24.In the reaction, 2C2H6(g) + 7O2(g) 4CO2(g)+ 6H2O(g) Determine the moles of CO2 and H2O formed when 2.00 moles of ethane are reactedwith 10.0 moles of oxygen. AP Chemistry Unit 111Denise DeMartino 25.Calculate the mass of calcium nitride formed when 50.0 g of calcium react with 50.0 g of nitrogen according to the reaction. 3Ca(s) + N2(g) Ca3N2(s) 26.A common laboratory method for determination of arsenic is described in the reaction, As2O3(aq) + 2I2(s) + 2H2O(l) As2O5(aq) + 4HI(aq) a)If 2.50 g of As2O3, 4.50 g of I2 and 4.00 g of H2O are mixed, and the reaction proceeds to completion, which reactant is the limiting reagent? b)Calculate the mass of As2O5 which is theoretically possible. c)If only 1.80 g of As2O5 is actually produced, determine the percent yield in the reaction. AP Chemistry Unit 112Denise DeMartino 27.An industrial method for the production of elemental zinc from its ore is to roast the crude ore in oxygen and then react it with CO.The following reactions describe the chemical process, 2ZnS(s) + 3O2(g) 2ZnO(s) + 2SO2(g) ZnO(s) + CO(g) Zn(s) +CO2(g) A 10.0 kg sample of an ore containing ZnS was chemically treated according to the reactions described above producing 2.85 kg of Zn.Determine the percentage of ZnS contained in the original sample of the ore. 28.A 0.00300 g sample of napthalene, a compound containing only carbon and hydrogen, was burned in excess oxygen to give 0.0103 g of CO2.Determine the empirical formula of napthalene.The formula weight of napthalene is 128 u, determine the molecular formula. AP Chemistry Unit 113Denise DeMartino AP Chemistry Unit 114Denise DeMartino AP Chemistry Unit 115Denise DeMartino AP Chemistry Unit 116Denise DeMartino AP Chemistry Unit 117Denise DeMartino AP Chemistry Unit 118Denise DeMartino AP Chemistry Unit 119Denise DeMartino