At a certain temperature the rate of this reaction is first order in N₂O5 with a rate constant of 0.0125 s¯¹: 2N₂O5 (g) → 2N₂O4 (8) + 0₂ (8) Suppose a vessel contains N₂O5 at a concentration of 1.14M. Calculate the concentration of N₂O5 in the vessel 88.0 seconds later. You may assume no of reaction is important. Round your answer to 2 significant digits.

The label on a bottle of 3% (by volume) hydrogen peroxide, H2O2, purchased at a grocery store, states that the solution should be stored in a cool, dark place. H2O2decomposes slowly over time, and the rate of decomposition increases with an increase in temperature and in the presence of light. However, the rate of decomposition increases dramatically if a small amount of powdered MnO- is added to the solution. The decomposition products are H2O and O2. MnO2 is not consumed in the reaction. Write the equation for the decomposition of H2O2. What role does MnO2 play? In the chemistry lab, a student substituted a chunk of MnO2 for the powdered compound. The reaction rate was not appreciably increased. WTiat is one possible explanation for this observation? Is MnO2 part of the stoichiometry of the decomposition of H2O2?

The following rate constants were obtained in an experiment in which the decomposition of gaseous N2O; was studied as a function of temperature. The products were NO, and NO,. Temperature (K) 3.5 x 10_i 298 2.2 x 10"4 308 6.8 X IO-4 318 3.1 x 10 1 328 Determine Etfor this reaction in kj/mol.

Explain what is meant by the average rate of a reaction.

Substances that poison a catalyst pose a major concern for many engineering designs, including those for catalytic converters. One design option is to add materials that react with potential poisons before they reach the catalyst. Among the commonly encountered catalyst poisons are silicon and phosphorus, which typically form phosphate or silicate ions in the oxidizing environment of an engine. Group 2 elements are added to the catalyst to react with these contaminants before they reach the working portion of the catalytic converter. If estimates show that a catalytic converter will be exposed to 625 g of silicon during its lifetime, what mass of beryllium would need to be included in the design?

Nitrogen dioxide reacts with carbon monoxide by the overall equation NO2(g)+CO(g)NO(g)+CO2(g) At a particular temperature, the reaction is second order in NO2 and zero order in CO. The rate constant is 0.515 L/(mol s). How much heat energy evolves per second initially from 3.50 L of reaction mixture containing 0.0275 M NO2? See Appendix C for data. Assume the enthalpy change is constant with temperature.

The rate of the decomposition of hydrogen peroxide, H2O2, depends on the concentration of iodide ion present. The rate of decomposition was measured at constant temperature and pressure for various concentrations of H2O2and of KI. The data appear below. Determine the order of reaction for each substance, write the rate law, and evaluate the rate constant. Rate [H2OJ [Kll (mL min-’) (mol L ’) (mol L ’) 0.090 0.15 0.033 0.178 0.30 0.033 0.184 0.15 0.066

For a first order gas phase reaction A products, k = 7.2 104s1 at 660. K and k = 1.7 102s1 at 720. K. If the initial pressure of A is 536 torr at 295C, how long will it take for the pressure of A to decrease to 268 torr?

The following equation represents a reversible decomposition: CaCO3(s)CaO(s)+CO2(g) Under what conditions will decomposition in a closed container proceed to completion so that no CaCO3 remains?

As with any drug, aspirin (acetylsalicylic acid) must remain in the bloodstream long enough to be effective. Assume that the removal of aspirin from the bloodstream into the urine is a lirst-order reaction, with a half-life of about 3 hours. The instructions on an aspirin bottle say to take 1 or 2 tablets every 4 hours. If a person takes 2 aspirin tablets, how much aspirin remains in the bloodstream when it is time for the second dose? (A standard tablet contains 325 mg of aspirin.)