CS2(g) →CS(g) + S(g) The rate law is Rate = k[CS2] where k = 1.6 × 10−6 s−¹. S What is the concentration of CS2 after 5 hours if the initial concentration is 0.25 M?

Isomerization of CH3NC occurs slowly when CH3NC is heated. CH3NC(g) CH3CN(g) To study the rate of this reaction at 488 K, data on [CH3NC] were collected at various times. Analysis led to the following graph. (a) What is the rate law for this reaction? (b) What is the equation for the straight line in this graph? (c) Calculate the rate constant for this reaction. (d) How long does it take for half of the sample to isomerize? (e) What is the concentration of CH3NC after 1.0 104 s?

Hydrogen iodide decomposes when heated, forming H2(g) and I2(g). The rate law for this reaction is [HI]/t = k[HI]2. At 443C, k = 30. L/mol min. If the initial HI(g) concentration is 1.5 102 mol/L, what concentration of HI(g) will remain after 10. minutes?

Candle wax is a mixture of hydrocarbons. In the reaction of oxygen with candle w ax in Figure 11.2, the rate of consumption of oxygen decreased with time after the flask was covered, and eventually' the flame went out. From the perspective of the kinetic-molecular theory, describe what is happening in the flask. FIGURE 11.2 When a candle burns in a closed container, the flame will diminish and eventually go out. As the amount of oxygen present decreases, the rate of combustion will also decrease. Eventually, the rate of combustion is no longer sufficient to sustain the flame even though there is still some oxygen present in the vessel.

At 573 K, gaseous NO2(g) decomposes, forming NO(g) and O2(g). If a vessel containing NO2(g) has an initial concentration of 1.9 102 mol/L, how long will it take for 75% of the NO2(g) to decompose? The decomposition of NO2(g) is second-order in the reactant and the rate constant for this reaction, at 573 K, is 1.1 L/mol s.

Ozone, O3, in the Earths upper atmosphere decomposes according to the equation 2 O3(g) 3 O2(g) The mechanism of the reaction is thought to proceed through an initial fast, reversible step followed by a slow, second step. Step 1: Fast, reversible O3(g) O2(g) + O(g) Step 2: Slow O3(g) + O(g) 2 O2(g) (a) Which of the steps is rate-determining? (b) Write the rate equation for the rate-determining step

For the reaction A+BC, explain at least two ways in which the rate law could be zero order in chemical A.

The isomerization of cyclopropane, C3H6, is believed to occur by the mechanism shown in the following equations: C3H6+C3H5k1C3H6+C3H6(Step1)C3H6k2C2=CHCH3(Step2) Here C3H6 is an excited cyclopropane molecule. At low pressure, Step 1 is much slower than Step 2. Derive the rate law for this mechanism at low pressure. Explain.

At 500 K in the presence of a copper surface, ethanol decomposes according to the equation C2H5OH(g)CH3CHO(g)+H2(g) The pressure of C2H5OH was measured as a function of time and the following data were obtained: Time(s) PC2H5OH(torr) 0 250. 100. 237 200. 224 300. 211 400. 198 500. 185 Since the pressure of a gas is directly proportional to the concentration of gas, we can express the rate law for a gaseous reaction in terms of partial pressures. Using the above data, deduce the rate law, the integrated rate law, and the value of the rate constant, all in terms of pressure units in atm and time in seconds. Predict the pressure of C2H5OH after 900. s from the start of the reaction. (Hint: To determine the order of the reaction with respect to C2H5OH, compare how the pressure of C2H5OH decreases with each time listing.)

The thermal decomposition of nitryl chloride, NO2Cl, 2NO2Cl(g)2NO2(g)+Cl2(g) is thought to occur by the mechanism shown in the following equations: NO2Clk1NO2+Cl(slowstep)NO2Cl+Clk2NO2+Cl2(faststep) What rate law is predicted by this mechanism?