Reaction Rates (College Board AP Chemistry)

Answer the following questions about the isomers fulminic acid and isocyanic acid.

Two possible Lewis electron-dot diagrams for fulrninic acid , HCNO, are shown below.

Explain why the diagram on the left is the better representation for the bonding in fulrninic acid. Justify your choice based on formal charges.

Fulminic acid can convert to isocyanic acid according to the equation below.

   HCNO(g)        HNCO(g)   

fulminic acid    isocyanic acid

Using the Lewis electron-dot diagrams of fulrninic acid and isocyanic acid shown in the boxes above and the table of average bond enthalpies below, determine the value of ΔH° for the reaction of  HCNO(g) to form HNCO(g).

A student claims that ΔS°  for the reaction is close to Explain why the student's claim is accurate.

Which species, fulrninic acid  (HCNO) or isocyanic acid  (HNCO), is present in higher concentration  at equilibrium at 298 K ? Justify your answer in terms of thermodynamic favorability and the equilibrium constant.

The ammonium salt of isocyanic acid is a product of the decomposition of urea, CO(NH₂)₂ ,  represented  below.

CO(NH₂)₂(aq) NH⁴⁺(aq) + OCN⁻(aq)

A student studying the decomposition reaction runs the reaction at 90°C. The student collects data on the concentration of urea as a function of time, as shown by the data table and the graph below.

The student proposes that the rate law is rate = k[CO(NH₂)₂] .

The student learns that the decomposition reaction was run in a solution with a pH of 13. Briefly describe an experiment, including the initial conditions that you would change and the data you would gather, to determine whether the rate of the reaction depends on the concentration of  OH⁻(aq).