Chemical Kinetics Assignment Help

#2

Iron(III) chloride is reduced by tin(II) chloride.

2FeCl3(aq) + SnCl2(aq) 2FeCl2(aq) + SnCl4(aq)

The concentration of Fe3+ ion at the beginning of an experiment was 0.0509 M. After 2.66 min, it was 0.0280 M. What is the average rate of reaction of FeCl3 in this time interval?

Cyclobutane, C4H8, consisting of molecules in which four carbon atoms form a ring, decomposes, when heated, to give ethylene.

C4H8(g) 2C2H4(g)

The reaction is first order. In an experiment, the initial concentration of cyclobutane was 0.0015 M. If the rate constant is 5.09 x 10-4 /s, what was the concentration of cyclobutane after a total of 493 s?

(Type your answer using the format 8.050e-3 for 8.050 x 10-3.)

13 #6

In the presence of excess thiocyanate ion, SCN–, the following reaction is first order in iron(III) ion, Fe3+; the rate constant is 1.27 /s.

Fe3+(aq) + SCN–(aq) Fe(SCN)2+(aq)

How many seconds would be required for the initial concentration of Fe3+ to decrease to 50 % left?

13 #7

Consider the following decomposition reaction according to the following equation:

Chemical Kinetics Assignment Help Through Online Tutoring and Guided Sessions from AssignmentHelp.Net

C(g) A(g) + B(g)

The activation energy for the forward reaction is 313 kJ; the ?H is 184 kJ. What is the activation energy for the reverse reaction?

13 #8

The reaction

2X(g) 2Y(g) + Z(g)

has rate-constant values for the reaction of X of 8.8e-06 /s at 350 K and 5.6e-04 /s at 400 K. Calculate activation energy for the reaction.

13 #9

The rate of a particular reaction quadruples when the temperature is increased from 270 K to 280 K. Calculate the activation energy for this reaction.

13 #12

A compound decomposes by a first-order reaction. The concentration of compound decreases from 0.1180 M to 0.0950 M in 5.2 min. What fraction of the compound remains after 6.9 min?

13 #14

The reaction of water with CH3Cl in acetone as a solvent is represented by the equation

CH3Cl + H2O CH3OH + HCl

The rate of the reaction doubles when the concentration of CH3Cl is doubled and it quadruples when the concentration of H2O is doubled.

Calculate k if CH3OH is formed at a rate of 1.50 M/s when [CH3Cl] = [H2O] = 0.49 M.

M-2s-1

13 #15

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 per second initially from 5.07 L of reaction mixture containing 0.0250 M NO2? See the Appendix on Thermodynamic Quantities for Substances and Ions at 25 for data. Assume the enthalpy change is constant with temperature.

13 #16

Nitric oxide reacts with hydrogen as follows:

2NO(g) + H2(g) N2O(g) + H2O(g)

The rate law is – [H2] / t = k[NO]2[H2], where k is 1.10 × 10-7 L2/(mol2•s) at 826 C. In a vessel at 826 C the partial pressures of NO and H2 are 131 mmHg and 381 mmHg, respectively. What is the rate of decrease of partial pressure of NO?

14 #2

A 4.00-L vessel contained 0.0199 mol of phosphorus trichloride, 0.0175 mol of phosphorus pentachloride and 0.0901 mol of chlorine at 230 C in an equilibrium mixture. Calculate the value of Kc for the reaction

PCl3(g) + Cl2(g) PCl5(g)

14 #6

Initially a mixture contains 0.828 mol each of N2 and O2 in a 6.53-L vessel. What is the molarity of NO when equilibrium is reached at 3900 C. The reaction is

N2(g) + O2(g) 2NO(g)

and Kc = 0.0123 at 3900 C.

14 #10

An equilibrium mixture of SO3, SO2 and O2 at 727 C is 0.0155 M SO3, 0.0056 M SO2 and 0.0020 M O2.

What is the value of Kc for the following reaction?

SO2(g) + ½O2(g) SO3(g)

14 #12

Iodine monobromide, IBr, occurs as brownish-black crystals that vaporize with decomposition:

2IBr(g) I2(g) + Br2(g)

The equilibrium constant Kc at 100 C is 0.026. If 0.046 mol IBr is placed in a 1.1-L vessel at 100 C, what are the moles of I2 at equilibrium in the vapor?

14 #13

Dinitrogen tetroxide, N2O4, is a colorless gas (boiling point, 21 C), which dissociates to give nitrogen dioxide, NO2, a reddish-brown gas.

N2O4(g) 2NO2(g)

The equilibrium constant Kc at 25 C is 0.125. What percentage of dinitrogen tetroxide is dissociated when 0.0360 mol N2O4 is placed in a 2.78-L flask at 25 C?

14 #16

The following reaction is important in the manufacture of sulfuric acid.

SO2(g) + ½O2(g) SO3(g)

At 900 K, 0.0215 mol of SO2 and 0.0150 mol of O2 are sealed in a 1.00-L reaction vessel. When equilibrium is reached, the concentration of SO3 is determined to be 0.0175 M. Calculate Kc for this reaction.

14 #17

Phosgene was used as a poisonous gas in World War I. At high temperatures it decomposes as follows:

COCl2(g) CO(g) + Cl2(g)

With Kc = 4.6 x 10-3 at 800 K.

A sample of 2.30 g of COCl2 is placed in a 2.51-L reaction vessel and heated to 800K. What fraction of COCl2 has decomposed?

14 #18

When 0.0265 mol of NO and 1.666 g of bromine are placed in a 1.00-L reaction vessel and sealed, the mixture reacts and the following equilibrium is established:

2NO(g) + Br2(g) 2NOBr(g)

At 25 C the equilibrium pressure of nitrosyl bromide is 0.438 atm. What is Kp?

14 #19

Antimony(V) chloride, SbCl5, dissociates on heating to give antimony(III) chloride, SbCl3 and chlorine.

SbCl5(g) SbCl3(g) + Cl2(g)

A closed 3.43-L vessel initially contains 0.0141 mol SbCl5. What is the total pressure at 248 C when equilibrium is achieved? The value of Kc at 248 C is 2.50 x 10-2.