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When there is an increase in temperature of a system the rate of reaction often increases.  Which of the following best explains why this happens according to the collision theory?          1     The concentrations increase with temperature.        2     The number of collision with the sufficient kinetic energy increases with temperature.        3     The number of collisions per unit time increases with temperature.        4     The orientation of the molecules change with temperature.

Given the two reactions shown with their equilibrium constants,              PCl3(g)    +  Cl2(g)    –> PCl5(g)                                K1               2 NO(g)  +  Cl2(g)   –> 2 NOCl(g)                           K2         What is the equilibrium constant for the reaction,                    PCl5(g)  +  2 NO(g)  –> PCl3(g)  +  2 NOCl(g)

What is the molecularity of the following elementary reaction? NH2Cl(aq) + OH– (aq) → NHCl– (aq) + H2O(l)  

Nitrogen monoxide reacts with bromine at elevated temperatures according to the equation   2NO(g) + Br2(g)  –>  2NOBr(g)        In a certain reaction mixture the rate of formation of NOBr(g) was found to be 4.50 x 10‑4 mol L‑1 s‑1.  What is the rate of consumption of Br2(g)?

The initial concentration of a reactant in a first order reaction is 0.620 M.  What will be its concentration after 3 half-lives have passed?

A reaction has the rate law, rate = k[A][B]3.  What is the overall order of the reaction?

An isomerization reaction of a substance, A, is first order.  In a laboratory class one student group found that 28.5% of A had isomerized after a period of 15.0 minutes when the temperature was maintained at 84.5 °C.  What is the half-life of substance A at that temperature? 

The reaction, 2 SO3(g)  2 SO2(g)  +  O2(g) is endothermic.  Predict what will happen if the temperature is increased.

Most heterogeneous reactions are slower than similar homogeneous reactions.  Which of the following best explains why?

The reaction system CS2(g) + 4H2(g)  CH4(g) + 2H2S(g) is at equilibrium. Which of the following statements describes the behavior of the system if the partial pressure of carbon disulfide is reduced?