For each of the following gas-phase reactions, indicate how the rate of disappearance of each reactant is related to the rate of appearance of each product: \(\begin{array}{l}{\text { (a) } \mathrm{H}_{2} \mathrm{O}_{2}(g) \longrightarrow \mathrm{H}_{2}(g)+\mathrm{O}_{2}(g)} \\ {\text { (b) } 2 \mathrm{N}_{2} \mathrm{O}(g) \longrightarrow 2 \mathrm{N}_{2}(g)+\mathrm{O}_{2}(g)} \\ {\text { (c) } \mathrm{N}_{2}(g)+3 \mathrm{H}_{2}(g) \longrightarrow 2 \mathrm{NH}_{3}(g)} \\ {\text { (d) } \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}(g) \longrightarrow \mathrm{C}_{2} \mathrm{H}_{4}(g)+\mathrm{NH}_{3}(g)}\end{array}\)

Short Answer

Expert verified
For each of the given gas-phase reactions: (a) -1 * d[H2O2]/dt = +1 * d[H2]/dt = +1 * d[O2]/dt (b) -2 * d[N2O]/dt = +2 * d[N2]/dt = +1 * d[O2]/dt (c) -1 * d[N2]/dt = -3 * d[H2]/dt = +2 * d[NH3]/dt (d) -1 * d[C2H5NH2]/dt = +1 * d[C2H4]/dt = +1 * d[NH3]/dt

Step by step solution

01

(a) Reaction H2O2(g) → H2(g) + O2(g)

In this reaction, we have: 1 mole of H2O2(g) → 1 mole of H2(g) + 1 mole of O2(g). The rate of disappearance of H2O2 is equal to the rate of appearance of H2 and O2, since they are in a 1-to-1 ratio. Therefore, we can write: Rate of disappearance of H2O2 = -d[H2O2]/dt Rate of appearance of H2 = +d[H2]/dt Rate of appearance of O2 = +d[O2]/dt Since they are in a 1-to-1 ratio: -1 * d[H2O2]/dt = +1 * d[H2]/dt = +1 * d[O2]/dt
02

(b) Reaction 2 N2O(g) → 2 N2(g) + O2(g)

In this reaction, we have: 2 moles of N2O(g) → 2 moles of N2(g) + 1 mole of O2(g). The stoichiometric coefficients indicate the relationship between the disappearance of N2O and the appearance of N2 and O2. We can write: Rate of disappearance of N2O = -d[N2O]/dt Rate of appearance of N2 = +d[N2]/dt Rate of appearance of O2 = +d[O2]/dt Since they are in a 2-to-2-to-1 ratio: -2 * d[N2O]/dt = +2 * d[N2]/dt = +1 * d[O2]/dt
03

(c) Reaction N2(g) + 3 H2(g) → 2 NH3(g)

In this reaction, we have: 1 mole of N2(g) + 3 moles of H2(g) → 2 moles of NH3(g). The stoichiometric coefficients indicate the relationship between the disappearance of N2 and H2, and the appearance of NH3. We can write: Rate of disappearance of N2 = -d[N2]/dt Rate of disappearance of H2 = -d[H2]/dt Rate of appearance of NH3 = +d[NH3]/dt Since they are in a 1-to-3-to-2 ratio: -1 * d[N2]/dt = -3 * d[H2]/dt = +2 * d[NH3]/dt
04

(d) Reaction C2H5NH2(g) → C2H4(g) + NH3(g)

In this reaction, we have: 1 mole of C2H5NH2(g) → 1 mole of C2H4(g) + 1 mole of NH3(g). The rate of disappearance of C2H5NH2 is equal to the rate of appearance of C2H4 and NH3, since they are also in a 1-to-1 ratio. We can write: Rate of disappearance of C2H5NH2 = -d[C2H5NH2]/dt Rate of appearance of C2H4 = +d[C2H4]/dt Rate of appearance of NH3 = +d[NH3]/dt Since they are in a 1-to-1-to-1 ratio: -1 * d[C2H5NH2]/dt = +1 * d[C2H4]/dt = +1 * d[NH3]/dt

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Most popular questions from this chapter

As described in Exercise 14.41 , the decomposition of sulfuryl chloride \(\left(\mathrm{SO}_{2} \mathrm{Cl}_{2}\right)\) is a first-order process. The rate constant for the decomposition at 660 \(\mathrm{K}\) is \(4.5 \times 10^{-2} \mathrm{s}^{-1}\) .half-life for this reaction? (b) If you start with 0.050\(M \mathrm{I}_{2}\) at this temperature, how much will remain after 5.12 s assuming that the iodine atoms do not recombine to form \(\mathrm{I}_{2}\) ?

Hydrogen sulfide \(\left(\mathrm{H}_{2} \mathrm{S}\right)\) is a common and troublesome pollutant in industrial wastewaters. One way to remove \(\mathrm{H}_{2} \mathrm{S}\) is to treat the water with chlorine, in which case the following reaction occurs: $$ \mathrm{H}_{2} \mathrm{S}(a q)+\mathrm{Cl}_{2}(a q) \longrightarrow \mathrm{S}(s)+2 \mathrm{H}^{+}(a q)+2 \mathrm{Cl}^{-}(a q)$$ The rate of this reaction is first order in each reactant. The rate constant for the disappearance of \(\mathrm{H}_{2} \mathrm{S}\) at \(28^{\circ} \mathrm{C}\) is \(3.5 \times 10^{-2} \mathrm{M}^{-1} \mathrm{s}^{-1}\) . If at a given time the concentration of \(\mathrm{H}_{2} \mathrm{S}\) is \(2.0 \times 10^{-4} \mathrm{M}\) and that of \(\mathrm{Cl}_{2}\) is \(0.025 \mathrm{M},\) what is the rate of formation of \(\mathrm{Cl}^{-} ?\)

The decomposition of hydrogen peroxide is catalyzed by iodide ion. The catalyzed reaction is thought to proceed by a two-step mechanism: $$ \begin{array}{c}{\mathrm{H}_{2} \mathrm{O}_{2}(a q)+\mathrm{I}^{-}(a q) \longrightarrow \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{IO}^{-}(a q) \text { (slow) }} \\ {\mathrm{IO}^{-}(a q)+\mathrm{H}_{2} \mathrm{O}_{2}(a q) \longrightarrow \mathrm{H}_{2} \mathrm{O}(l)+\mathrm{O}_{2}(\mathrm{g})+\mathrm{I}^{-}(a q) \text { (fast) }}\end{array} $$ \(\begin{array}{l}{\text { (a) Write the chemical equation for the overall process. }} \\ {\text { (b) Identify the intermediate, if any, in the mechanism. }} \\ {\text { (c) Assuming that the first step of the mechanism is rate }} \\ {\text { determining, predict the rate law for the overall process. }}\end{array}\)

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