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Unformatted text preview: STUDY GUIDE Chapter 4 Review 1. How many Fe atoms and how many moles of Fe atoms are in 500.0 g of iron? 5.39E24 atoms Fe 2. Aluminum metal is produced by passing an electric current through a solution of aluminum oxide (Al2O3) dissolved in molten cryolite (Na3AlF6). Calculate the molar masses of Al2O3 and Na3AlF6. Al2O3 = 101. 96 g/mol and Na3AlF6= 209.95 g/mol 3. Calculate the molar mass of Ca3(PO4)2. a. How many moles are present in 1.00 g of the compound? 3.22E-3 mol b. How many grams are present in 5.00 mol of the compound? 1.55E3 g c. How many grams of phosphorous are present in 5.00 mol of the compound? 310 g 4. Fungal laccase, a blue protein found in wood-rotting fungi, is 0.390% Cu by mass. If a fungal laccase molecule contains 4 copper atoms, what is the molar mass of fungal laccase? 6.54E4 g/mol 5. Balance the eguations: a. b. c. Cu(s) + Zn(s) + Au2S3(s) + 2AgNO3(aq) 2HCl(aq) 3 H2(g) → → 2Ag(s) + ZnCl2(aq) + 2 Au(s) + Cu(NO3)2(aq) H2(g) → 3H2S(g) 6. Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation is C7H6O3 + C4H6O3 → C9H8O4 + HC2H3O2 a. What is the mass of the acetic anhydride is needed to completely consume 1.00 X 102 g salicylic acid? 73.9 g b. What is the maximum mass of aspirin (the theoretical yield) that could be produced in this reaction? 1.30E2 g 7. Consider the reaction: Mg(s) + I2(s) → MgI2(s) Identify the limiting reagent in each of the reaction mixtures below: a. 0.16 mol Mg and 0.25 mol I2 b. 0.14 mol Mg and 0.14 mol I2 Neither c. 6.078g Mg and 63.46 g I2 Neither d. 1.00 g Mg and 2.00g I2 8. Mercury and bromine will react with each other to produce mercury(II) bromide: Hg(l) + Br2(l) → HgBr2(s) a. What mass of HgBr2 can be produced from the reaction of 10.0g Hg and 9.00g Br2? 18 g What mass of which reagent is left unreacted? 1.03 g b. What mass of HgBr2 can be produced from the reaction of 5.00 ml mercury (density =13.6 g/ml) and 5.00 ml bromine (density =3.10 g/ml)? 35 g Chapter 15 Review 1. Distinguish among the initial rate- instantaneous rate at t=0 seconds, average rate= rate measured over time, and instantaneous rate= rate at a specific time of a chemical reaction. Which of the rates usually has the largest value? Initial rate 2. Define each: a. Elementary step- single step in a reaction mechanism. b. Reaction mechanism- series of elementary steps to give overall balanced equation c. Rate-determining step = slowest step in a reaction mechanism 3. For the reaction: 2H2(g) The observed rate law is Rate= k[NO]2[H2] Which of these changes would affect the value of the rate constant k? a. Increasing the partial pressure of hydrogen gas b. Changing the temperature + 2NO(g) → N2(g) + 2H2O(g) c. Using an appropriate catalyst 4. Consider the reaction 4PH3(g) → P4(g) + 6H2(g) If, in a certain experiment, over a specific time period, 0.0048 mol 4PH3 is consumed in a 2.0 L container each second of the reaction, what are the rates of production of P4 =6.0E-4 mol/L-s and H2 = 3.6E-3 mol/L-s in this experiment? 5. What are the units of each of the following if the concentrations are expressed in moles per liter and the time in seconds? a. Rate of a chemical reaction mol/L-s b. Rate constant for a zero order rate law mol/L-s c. Rate constant for a first order rate law 1/s d. Rate constant for a second order rate law L/mol-s 6. The rate law for the reaction Cl2(g) + CHCl3(g) → HCl(g) + CCl4(g) Rate= k [Cl2]1/2[CHCl3] What are the units for k, assuming time in seconds and concentrations in mol/L? L1/2/mol1/2-s 7. The reaction 2NO(g) + Cl2(g) → 2NOCL(g) Was studied at -10C. The following results were obtained where Rate= -∆[ Cl2] ∆t Initial Conc. NO 0.1 0.1 0.2 Initial Conc. Cl2 0.1 0.2 0.2 Initial rate 0.18 0.36 1.45 / a. What is the rate law? Rate= k [NO]2[Cl2] b. What is the value of the rate constant? K=180 L2/mol2-min 8. You have the following reaction 2ClO2(aq) + Where 2OH-(aq) → ClO3-(aq) + ClO2-(aq) + H2O(l) Rate = - ∆[ ClO2] ∆t / Initial Conc. ClO 0.05 0.1 0.1 Initial Conc. OH 0.1 0.1 0.05 Initial rate 5.75E 02 2.30E 01 1.15E 01 a. Determine the rate law and the value of the rate constant. Rate= k[ClO2]2[OH] b. What would be the initial rate for an experiment with [ClO2]o =0.175M and [OH]o=0.0844M? 0.594 mol/L-s 9. A general reaction aA → bB At a particular temperature and [A]o=2.8E10-3M, concentration versus time data were collected for this reaction, and a plot of 1/[A] versus time resulted in a straight line with a slope of 3.60E10-2 L/mol-s. a. Determine the rate law rate=k[A]2, the integrated rate law 1/[A] = kt + 1/[A]o, and the value of the rate constant for this reaction k=slope=3.6E-2 L/mol-s. b. Calculate the half-life for this reaction. 9.92E3 s c. How much time is required for the concentration of A to decrease to 7.00E-4 M? 2.98E4 s ...
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- Fall '08