Chemical Reactions: Initial Rates, Equilibria, and Kinetics, Exercises of Chemistry

Download Chemical Reactions: Initial Rates, Equilibria, and Kinetics and more Exercises Chemistry in PDF only on Docsity! 1. For the following reaction, the initial rate of formation of hydrogen gas is 0.15 mol/Lsec. 3 ( ) 4 ( ) 2 ( )4 6 g g gPH P H⎯⎯→ + What is the initial rate of depletion of phosphorus trihydride? 0.10 mol/L-s 2. Hydrogen peroxide decomposes under certain conditions in a first-order reaction with rate constant equal to 1.06 x 10-3 min-1. 2 2 ( ) 2 ( ) 2( )2 2 aq l gH O H O O→ + What fraction of hydrogen peroxide will remain after exactly one hour? 3(1.06 10 )(60) 0.938kt o A e e A −− − ×= = = 3. For a reaction to be second-order with respect to one reactant, a plot of what versus time will yield a straight line? A plot of 1/[concentration] will yield a straight line. 4. The following reaction is a bimolecular reaction: ( ) 2 ( ) 2 ( )2 g g gHI H I→ + a. What is the rate law for this reaction? rate = k[HI]2 b. What does it mean to be bimolecular (with respect to the mechanism)? It means that two HI molecules will collide in the rate-determining step. Docsity.com 5. If the rate constant for the reaction in problem 4 is 2.15 x 10-8 L/mol-s at 650 K and 2.39 x 10-7 L/mol-s at 700 K, what is the activation energy for the reaction? 8 7 2.15 10 1 1ln 2.39 10 8.314 650 700 182000 / a aE J mol E− − ⎛ ⎞ −× ⎛ ⎞= −⎜ ⎟ ⎜ ⎟× ⎝ ⎠⎠ = ⎝ 6. Consider the reaction, 2 ( ) 2 ( ) 3 ( )2 2 g g gSO O SO+ → a. Write an equilibrium expression for this reaction: 3 2 2 2 2 SO SO O P K P P = b. If the total pressure is increased on the system at equilibrium, what will happen to restore equilibrium? An increase in total pressure will drive the reaction to the right in favor of less molecules of gas. 7. Consider the following chemical reaction with stated equilibrium constant, 9 2 3 ( ) 2 ( ) 2 ( )2 3 2.86 10g g g PNH N H K atm −→ + = × If 1.000 atm of ammonia is introduced into an empty flask, what will be the partial pressures of all three gases at equilibrium? 3 2 2 3 4 9 2 N 2 ( )(3 ) 272.86 10 (1 2 ) (1 2 ) 0.003198 0.9936 P 0.00320 0.00959 NH H P atm atm x x x x x P x atm − = = = × = = − − = Docsity.com