Exam #3 Study Guide
Popular in Chemistry
verified elite notetaker
Popular in Science
verified elite notetaker
This 41 page Study Guide was uploaded by Brian Zhong on Friday April 24, 2015. The Study Guide belongs to Chem 115 at a university taught by Dr. Martinez in Fall. Since its upload, it has received 786 views.
Reviews for Exam #3 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: 04/24/15
Chem 115 Test 3 Practice Problems Spring 2015 Name Section 1 You are given 150 mL of a 020 M aqueous solution of ammonium carbonate and 150 mL of 040 M aqueous solution of barium iodide These solutions are mixed and a precipitate forms Write the net ionic equa00n for this process include physical states Us What are the spectator ions for this process What is the limiting reactant P How many moles of the solid precipitate are formed e What are the nal concentrations for each of the ions in solution after precipitation f Is the solution electrically neutral 2 Write a balanced equation for the reaction of cyclodecane C10H20 l burning in oxygen gas include physical states a Is this reaction endothermic or exothermic b Is this a redox reaction Justify 3 In the reactions below label the Bronsted Lowry Acid Base Conjugate Acid and Conjugate Base HSOZaq H200 gt H2SO4aq OHaq NH3g H200 gt NH OHaq CH3COOaq H200 gt CH3COOHaq DH aq NH3g H2CO3aq gt NHZHaq HCO aq OU QD Q 4 In the following reaction identify the reducing and oxidizing agents Show your work by including oxidation states 01120 s Cr202 s gt Cu2 aq Cr3 aq 7 5 The theoretical yield of a certain reaction is 1200 g of F62 03 If the actual yield when the experiment is performed is 0213 mol Fe203 what is the percent yield 6 A standard solution is prepared for the analysis of uoxymesterone C20H29FO3 an anabolic steroid A stock solution is rst prepared by dissolving 168 mg of uoxymesterone in enough water to give a total volume of 5000 mL A 10 aL portion of this stock solution is taken out and then diluted to a nal volume of 10 mL Calculate the nal concentration of this new solution in M 7 If 250 mL of a 035 M HCl solution are needed to titrate 152 mL of a NaOH solution what is the concentration of the NaOH solution 8 Sulfuric acid forms in the following chemical reaction S02 9 02 g H20 1 gt H2SO4 aq Suppose 79 mol S02 55 mol of 02 and 40 mol of H20 are mixed together and the reaction proceeds until one of the reactants is used up a After balancing the chemical equation determine which molecule is the limiting reactant b How many moles of H2SO4 are produced c How many moles of each reactant remain 9 A piece of unknown metal with a mass of 120 g is heated to 10500C and dropped into 250 g of water at 2500C The nal temperature of the system is 2880C What is the speci c heat capacity of the metal 10 Consider the Diels Alder class reaction and associated table of enthalpies H c H C H HCCCH i H HCH 39339 I H H T Ll H C H H g H H g a H g The molar enthalpy of reaction AHmn for the above reaction is 200 kJmol What is the bond enthalpy for a CC bond in kJmol Bond AHb kJmol C C 350 C H 400 CC 11 A Copper Reaction Aqueous solutions of copperII sulfate and sodium phosphate are mixed to gether What happens MMsulfate 9606 gmol MMphosphate 9497 gmol a Write the balanced equation for the reaction that takes place including all physical states b What type of reaction is this Ionic precipitation reaction acid base reaction or redox reaction Explain your choice How many grams of sodium phosphate are needed to make 100 mL of a 01 M sodium phosphate solution What is the limiting reactant during the formation of the copper product in the reaction above when 30 mL of 01 M copperII sulfate solution is added to 25 mL of 01 M sodium phosphate solution Calculate how many grams of copper product can be theoretically produced from the reactants listed above in Part D Anna isolates 028 g of solid from the reactants above What is her percent yield for this step in the copper cycle 12 A Titration Antacids work by neutralizing the acid in your stomach There are a variety of antacids on the market but most are suspensions containing a metal hydroxide or carbonate compound a b C Write the balanced chemical equation for the neutralization of hydrochloric acid by magnesium hydroxide Include physical states A 100 mL sample of magnesium hydroxide of unknown concentration is diluted to 500 mL The diluted sample is titrated using 100 M hydrochloric acid If 700 mL of hydrochloric acid is required to reach the equivalence point how many moles of magnesium hydroxide are present in the dilute solution What is the molar concentration of the original undiluted sample of magnesium hydroxide 13 Calorimetry Instant cold packs used to ice athletic injuries on the eld contain ammonium nitrate and water separated by a thin plastic divider When the divider is broken the ammonium nitrate dissolves In a coffee cup calorimetry lab experiment a student dissolved 125 g ammonium nitrate in enough water to make a 250 mL of solution The initial temperature of the solution is 2580C and the nal temperature after the solid dissolves is 2190C a Calculate AH in kJmol for the dissolution process Use 10 gmL for the density of the solution and 4184 J g C as the speci c heat capacity for H20 b Is the dissolution of ammonium nitrate endothermic or exothermic Justify your answer by using the data c Which intermolecular forces are stronger the forces holding the ammonium nitrate together as a solid or the forces present between solute and solvent Explain your choice 14 Hess s Law The combustion of solid sulfur to form 803 gas occurs in two steps 2 S S 3 02g gt 2 803 g a What type of reaction ionic acid base redox is taking place during the combustion of sulfur above Justify your choice b Use the following reactions and given Hs to calculate ern for the combustion of sulfur 302 g gt s s 02 g AHmn 2968 kJ 2 802 g 02g gt 2 803 g AHmm 1978 kJ c Is the combustion of sulfur to form 803 gas exothermic or endothermic Justify your choice d How much heat is produced from the combustion of 50 g of elemental sulfur 15 Finding AHmn from AHb Given the following reaction 2 H28 g 3 02g gt 2 302g 2 H20 l a Draw the Lewis structure for each reactant and product b Calculate AHmn for the reaction above given the bond dissociation energies bond enthalpies AHb below H S 347 kJmol 00 495 kJmol 80 536 kJmol O H 467 kJmol c Is the reaction above exothermic or endothermic Justify your choice 16 Reactions in Solution NOTE For questions about the type of reaction choose from Ionic precip itation reaction acid base reaction or redox reaction For Explain your choice write exactly what is taking place during the reaction between the two reactants For example if something is being transferred like electrons or H then indicate the transfer from one reactant to the other a Aqueous solutions of sodium hydroxide and copperII nitrate are mixed 1 Write the balanced molecular equation for this reaction including physical states 2 Write the net ionic equation for this reaction including physical states 3 What type of reaction is this Explain your choice b Aqueous solutions of leadII nitrate and potassium iodide are mixed 1 Write the balanced molecular equation for this reaction including physical states 2 Write the net ionic equation for this reaction including physical states 3 What type of reaction is this Explain your choice c When a piece of Zn metal is put into an aqueous solution of hydrochloric acid H2 gas evolves and the Zinc dissolves into solution 1 Write the balanced molecular equation for this reaction 2 What type of reaction is this Explain your choice 17 18 19 20 21 22 23 24 25 26 27 d When solid calcium carbonate is exposed to aqueous hydrochloric acid the solid dissolves and a gas is produced 1 Write the balanced molecular equation for this reaction 2 What type of reaction is this Explain your choice Suppose you have a solution of silver nitrate and magnesium nitration Give an example of an another aqueous solution that could be used to precipitate the silver ions in an insoluble compound but leave the magnesium ions in solution Give an example of a compound that has ionic bonds and covalent bonds Concentrated HCl is commercially available as a 1500 M solution What volume in mL of 1500 M HCl is needed to make 250 mL of 300 M HCl What is the molar concentration of a potassium hydroxide solution made by dissolving 196 g of potas sium hydroxide into 700 mL of water Follow up How many grams of potassium hydroxide are needed to make 700 mL of 0500 M potassium hydroxide solution How many mL of the 0500 M solution can be made from the original 196 g of potassium hydroxide A solution of iron III chloride and sodium phosphate are mixed togher a Write the balanced net ionic equation for the reaction b Is this a redox reaction Justify Write a reaction for each of the following species with water and identify if each acts as an acid or a base a HPO4 b HNO3 c Cl In a reaction 025 mole of solid ironIII oxide reacts with excess solid aluminum to form solid aluminum oxide and solid iron 126 g of solid iron were produced a Write a balanced equation for this process b What was the yield for this reaction c Is this reaction is a redox reaction Justify What is the oxidation state of chromium in dichromate CrgO In the follwoing chemical reaction identify the oxidizing and reducing agents In which direction to the electons frlow during redox from oxidixing agent to reducing agent of the the other way around Zn s CuSO4 aq gt ZnSO4 aq Cu s Consider the following reaction 2 N2H4 N204 gt 3 N2 4 H20 a When 0350 moles of N204 react with excess N2H4 how many grams of N2 will be obtained b How many grams of N2H4 are needed to react with 0350 moles of N204 What are the products when a solution of perchloric acid and a solution of sodium carbonate are mixed together 28 29 30 31 32 33 34 What volume in mL of 120 M hydrochloric acid is required to titrate 420 mL of 0453 M barium hydroxide Liquid dinitrogen tetraoxide is produced by the reaction between nitrogen monoxide gas and oxygen gas When 075 moles of nitrogen monoxide gas are placed in a reaction ask with 050 moles of oxygen gas what will be present in the reaction ask at the end of the reaction assume the ask is sealed and nothing can escape When nitric acid reacts with aluminum hydroxide the products are typical of an acid base neutraliza tion reaction After 2500 mL of 125 nitric acid reacts with 1218 grams of aluminum which reagen will be in excess at the end of the reaction and by how much What is the molar concentration of sulfate in solution when 1000 g of iron III sulfate are dissolved in water to make 20 L of solution The neutralization reaction between calcium hydroxide and hydrochloric acid releases 151 kJ of heat for every mole of water produced How much heat is released with 167 g calcium hydroxide reacts with 125 g of hydrochloric acid A triprotic acid has a general formula of H3A and reacts with NaOH according to the following reaction H3A aq 3 NaOH aq gt 3 H20 1 Na3A aq A student titration 00591 grams of the acid with a solution of NaOH The endpoint of the titration was reached when 7380 mL of 0125 M NaOH was added What is the molar mass of the triprotic acid Calculate the moles of gas evolved when 0210 grams of magnesium carbonate reacts with 50 mL of 125 M hydrochloric acid MBonus If one mole of gas takes up 240 L what volume of gas is produced Chem 115 Review Problems Acid Base and Redox Chemistry amp Calorimetry Name SFSU ID 1 What is the original concentration of a barium hydroxide solution if concentration of hydroxide is 331 x 104 M 2 Consider the reaction NaOH aq HCl aq gt NaCl aq H20 1 You are given 3000 mL of a 00302 HCl solution You are also given a 00180 M aqueous solution of sodium hydroxide What volume in L of the NaOH solution is required to completely react with the HCl solution 3 A 3000 mL sample of an unknown HClO4 solutions requires titration with 2262 mL of 02000 M NaOH to reach the equivalence point Waht is the concentration of the unknown HClO4 solution 4 How much heat is transferred when 400 g of water is cooled from 100 C down to 000 C speci c heat of water is 418 J g C Is this an endothermic or exothermic process 5 You are given a solution of 0050 M of perchloric acid HClO4 a strong acid a Write the chemical equation for the reaction that occurs in this solution b What are the conjugate acid and base pairs in the solution c What is the concentration of hydronium in this solution 6 You are given a solution of 010 M of hydrocyanic acid HCN a weak acid a Write the chemical equation for the reaction that occurs in this solution b What are the conjugate acid and base pairs in the solution c Is the concentration of hydronium in this solution the same as the original concentration of HCN or less Why 7 For the following reactions assign oxidation states to each atom and identify the reducing and oxidizing agents a Mn0aq 3202 aq gt Mn02aq C02aq b IO3aq Iaq gt 12aq 8 Balance the following redox reaction Zn s HCl aq gt ZnC12 aq H2 g a Identify the reducing and oxidizing agents b What volume mL of 20 M HCl is required to convert 1962 g of Zn completely to products 9 A reaction between gases takes place in a balloon The balloon shrinks and cools Is this process endothermic or exothermic Explain 10 The enthalpy of neutralization for the reaction of strong acid With strong base is 600 kJ per mole of water produced How much energy Will be released When 2000 mL of 040 M HCl is mixed With and 1500 mL of 0500M NaOH 11 When 100 L of 200 M NaQSO4 solution at 300 C is added to 200 L of 0750 M BaNO32 solution at 300 C in a calorimeter a White solid forms and the temperature of the nal solution is 450 C Assuming that the speci c heat capacity C s of the solution is 600 J g C and that the density of the solution is 200 gmL calculate the enthalpy change per mole of BaSO4 formed 12 A 200 g hot block of iron 1268 C is placed against a 400 g cold block of gold 7315 C What will the nal temperature in C of the blocks be When they reach thermal equilibrium C 3 Fe 2 0400 Jg C C3Au 0100 Jg C Chem 115 Review Problems Enthalpy Hess s Law Bond Enthalpies Name SFSU ID 1 Consider the follwing generic chemical reactions A2B gtC3D AHmn150kJ 2C6D gtE AHmn100kJ Determine the AHmn for the following related equations aA2B gtE b 3C9D gt3A6B c C De AB 2 Calculate AHmn for the following reaction make sure equation is balanced Cos 02g gt C03O4s from the information given below 2 C00 8 gt 2 Co 8 02 g AHmn 500 kJmol 6 C00 8 02 g gt 2 C0304 s AHmn 300 kJmol 3 Consider the following chemical reaction N2 g 3 H2 g gt 2 NH3 g AHmn 92 kJmol What is AH when 045 g of N2 and 32 g of H2 react 4 Consider the equations given below gt H2g 02g AHTxn AHl CQH6g gt 2 3 AHTam AHQ 2 002g 3 H200 gt 02H6g 02g AHmn AH3 Give the expression for the AHmn for the reaction below in terms of AHl AH2 and AH3 03 02g gt 002g Bond Enthalpies kJmol 0H 450 CH 410 00 350 00 350 00 2 500 00 2 750 Ethanol CH3CH20H l and dimethyl ether CH3OCH3 l are isomers Calculate the enthalpy of the following reaction by using both Bond Enthalpies and Hess s Law How well does the bond enthalpy estimate compare to the Hess s Law answer CH3CH20Hl gt CH3OCH3 AH Cs H2 g 02 g gt CH3CH20H 1 AH 277kJmol Cs H2 g 02 g gt CH3OCH3 1 AH 270 kJmol Alcohols are proposed as fuel sources for the future and currently there are even cars that run on ethanol The balanced chemical equations for the complete combustion of a standard alkane fuel and an alcohol are CH3CH2CH3 g propane 5 02 g gt 3 C02 g 4 H20 g CH3CH20H20H 1 propanol g 02 g gt 3 002 g 4 H20 g The result of combustion of one mole of propane is the same as combustion of one mole of propanol three moles of carbon dioxide and four moles of water This means the difference in the energy content of the two fuels is due to the bond enthalpies of the reactants Calculate the enthalpy difference AIIzov opanol 39 AHpropanea in W MW Ma 22 a m 1 2 W4 A pray71m Naga LZQ Ca 4 AaZYag 6 a 6ng Vado74 bn 507 aqueow ampM5 7 L N Z ad 7 ZK ea HVM I Jou e Mo lu e ZVaV03a Zquotzj q quot3 W d rah0740 1K3605 4 7 Af z ag 9 ZUZag VIff J T 740 M0 VJ Mi979 gaz a rnaw 39 Moecuar egcm 4 a Ma cu f i in 16405er NA aka6 M74 gazw mz w fw Vr a ZJ 4 VIJE 0 QMM87 I om c efum bn V 53713 a Z a J WM27L 1 gt L lt l quot WWW w mMWaww r 1 7 l L 7 L 5t7r3c7Lmlvlquot fom 4276 mlf xx497 in L i c emfca 4074 dn 39 i TN 3 my 032 wagJ W W m9 om o egwa bn AJJ Veg393 461 fa ka om k JV rea074 om L 39 quot m w 2 L 5r zKacgLi37ampq g7 Wag74122 L 4 U and 6 are 90967461791 P quot r 39w n if w I 1 f x hd fom cljfr HCad Z aj J Z efri f Jzf I 39 A ma m a 4 HM way27mm W 7 6 y 2 m yaw Wiz fg r sfm 1M0 iMy 7514 f Z 740 9 74J6J LLLEhLLliLlIJJl 11 JJJJJJ 2d max wayWM iab ox Canz n vv oh 1461600 59174375 4744 foyg 7z 4maom7L d7 5047472 in J w om dig ofmhay amg wan j womenMM Jam z on a M DadMg A ifwit 10047431 140752 27Z af mm OMMM zm 6f mamwbn f Moaf 7 M amaumL a7AJaM76mgd Volume 075 Mu74bn bka E m MZZKM hJ 3 7 ma hij mfa zrwcz ne5 3 X na 7 mo 6 344 91 40 I 7m0 AaZfi ym grungy2 M f 79 446 OIL faW746 g Va 0 57ma Ma 6 739 ImoAa Tfnmmmv ma um k 055qu W191 AdJ Aa f r Vi1 010 tantam rm bn n Noaw fragMW Mo M AM 7 A 52 quot 5g xw 541379 50 74 tm T on en a om J fV 410W quotMMy 074 IVa 5 are r em 3401 071 dM6 10M7gxow7 l 7L mpMia
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'