Rate Expressions Worksheet1) Write the following for the reaction N2 + 3 H2  2 NH3- The rate expression for the reaction- The order of the reaction in each of the reagents- The overall order of the reaction2) The rate constant for the reaction HNO3 + NH3  NH4NO3 is 14.5 L / mol.sec. If the concentration of nitric acid is 0.050 M and the concentration of ammonia is 0.10 M, what will the rate of this reaction be?3) When two compounds, A and B, are mixed together, they form compound C, by a reaction that’s not well understood. Fortunately, the following rate information was experimentally determined, as shown below:[A] (mol/L) [B] (mol/L) Rate (mol/L.sec)0.050 0.050 4.0 x 10-30.10 0.050 8.0 x 10-30.050 0.10 1.6 x 10-2a) Determine the rate expression for this reaction.b) Determine the rate constant for this reaction.© 2004 Cavalcade Publishing, All Rights Reserved For chemistry help, visit www.chemfiesta.comRate Expressions Worksheet – Answers1) Write the following for the reaction N2 + 3 H2  2 NH3- The rate expression for the reaction- The order of the reaction in each of the reagents- The overall order of the reactionRate = k[N2][H2]3The reaction is first order in nitrogen and third order in hydrogen.The overall order of the reaction is fourth order.2) The rate constant for the reaction HNO3 + NH3  NH4NO3 is 14.5 L / mol.sec If the concentration of nitric acid is 0.050 M and the concentrationof ammonia is 0.10 M, what will the rate of this reaction be?Rate = k[HNO3][NH3]Rate = (14.5 L / mol.sec)(0.050 M)(0.10 M)Rate = 0.073 mol / L. sec3) When two compounds, A and B, are mixed together, they form compound C, by a reaction that’s not well understood. Fortunately, the following rate information was experimentally determined, as shown below:[A] (mol/L) [B] (mol/L) Rate (mol/L.sec)0.050 0.050 4.0 x 10-30.10 0.050 8.0 x 10-30.050 0.10 1.6 x 10-2a) Determine the rate expression for this reaction.When you double the concentration of A, the rate doubles, which suggests that the reaction is first order in A. When you double the concentration of B, the rate quadruples, which suggests that the reaction is second order in B. Using this to generate a rate equation,we get:Rate = k[A][B]2b) Determine the rate constant for this reaction.Plugging the concentrations into the equation with the rate, we solvefor k (incidentially, it doesn’t matter which trial we use – the numberswork out the same):4.0 x 10-3 mol/L.sec = k(0.05 mol/L)(0.05 mol/L)2k = 32 L2 / mol2.sec© 2004 Cavalcade Publishing, All Rights Reserved For chemistry help, visit www.chemfiesta.comNote: Rate constants may have a variety of strange units using L, mol, and sec. This is so the rate will always work out in mol/L.sec.© 2004 Cavalcade Publishing, All Rights Reserved For chemistry help, visit