Chemical kinetics Questions and Answers

For a reaction A P the energy of activation is 15 8 kcal at 298 K Calculate the number of activated molecules if we start with 1 mol of A considering Arhenius equation to be valid Given e 26 51 3 067 10 2 Options 1 1 031 1021 2 1 847 10 2 3 5 86 x 1023 4 3 067 x 10 2

12 He and Ar are monoatomic gases and their atomic weights are 4 and 40 respectively Under simila conditions He will diffuse through semi permeabl membrane 1 3 16 times as fast as Ar 2 7 32 times as fast as Ar 3 1 58 times as fast as Ar

3 For the equilibrium AB the variation of the rate of the forward a and reverse b reaction with time is given by A C Rate of reaction ate of reaction a b Time b equilibrium equilibrium B D Rate of reaction Vorrat je dje 6 Lime equilibrium equilibrium

0 0755 g of selenium vapours occupying a volume of 114 2 mL at 973 K exerts pressure atm For the reaction Se g 3 Se g Degree of dissociation of Se 0 59 Which of the following statement s is are correct regarding above statemen 185 760 A Value of K is 0 1687 C Value of K 0 1687 0 0821x973 B Value of K 0 2645 10 4 0 0821x973 973 D Value of K

conc 20 days Time R P Follows the above conversion graph and this first order reaction occurring at 27 C then 10 molecules are in activated state Find the maximum rate constant A 3 46 10 day C 10 day B 3 46 10 day X D can t be determined

Convert these reaction rates to molarity using beers law Reaction rate is 0 013 9 0 0 0002000 10 0 0002000 10 0 0001500 10 0 0002500 10 0 001300 00 0 0001500 00 0 0001000 01 0 0001500 10 E406H 11 12 0 0002000 0 0007501 0 0001000 0 0001500 0 0001500 0 0001500 0 0002500 0 0001500 0 0002000 0 0002000 0 0001500 0 0002000 0 0002500 0 0001500 0 0001500 0 0003000

An engineering student purchased piece of amber from a local shopping mall The amber contained the remains of an beetle Curious to know whether the gem is genuine or not the student takes the sample to the laboratory and determines the concentration of Carbon 14 5730 years After extracting a piece of the trapped beetle with a fine drill instrument analysis reported that the concentration of Carbon 14 is now only 94 If there was 100 Carbon 14 when the beetle was trapped how old is the gem and is it genuine Trivia Amberification is a polymerization process that takes several millions of years The youngest amber is around 16 million years old and can be found in the Dominican Republic 23 million years old genuine O 51 million years old genuine O 23 000 years old counterfeit O 510 years old counterfeit

The partial pressure of hydrogen in a fla containing 2 g H and 32 g SO is 1 1 16th of total pressure 2 1 9th of total pressure 3 2 3rd of total pressure 4 1 8th of total pressure

0 The results given in the below table were obtained during kinetic studies of the following reaction 2A B C D 1 Experiment A moll 1 0 1 II 0 1 III 0 2 IV V X 0 3 B molL 0 1 0 2 0 1 0 2 Y Initial rate molL min 6 00 x 10 3 2 40 x 10 2 1 20 x 10 2 7 20 x 10 2 2 88 x 107 X and Y in the given table are respectively A 0 3 0 4 B 0 4 0 3 C 0 4 0 4 D 0 3 0 3

Which condition defines a reaction at equilibrium O The concentration of products is equal to the concentration of reactants The reactions forming products and reactants come to a stop The concentration of products is greater than the concentration of reactants The rate of the forward reaction is equal to the rate of the reverse reaction The concentration of reactants is greater than the concentration of products

The rate law for the oxidation of Nitric oxide 2NO O NO is given by rate KNO O If the volume of reaction vessel is reduced to 1 4 th of its original volume then how will the rate of reaction will change consider initial rate and final rate as R and R

For a given reaction AH 35 5 kJ mol and AS 83 6 JK 1 mol 1 The reaction is spontaneous at Assume that AH and AS do not vary with temperature at high Temp NEET 2017 1 T 425 K 2 T 425 K 3 All temperatures 4 T 298 K

What is the single particle collisional frequency at sea level with T 280 K and P 1 15 atm The corresponding single particle collision frequency is reported as 10 0 s in the CRC Handbook of Chemistry and Physics 62d ed p F 171 Express your answer in reciprocal seconds to two significant figures AEO 211 4 02 4 02 10 S 1

Concentration of A B and C vs time graph for the reaction A 2B C is given below The experimental rate law of the reaction is obtained as Rate K A Choose the correct statement s from the below given options Use In2 0 7 and In3 1 B A B C N One More Correct Answer s D Concentration mol L t 50 time sec At time t A B t 21 43 sec nearly Half life of reaction 50 sec Rate constant k In 2 50 sec 1 C A

In a diffusion controlled reaction A B P at 43 53 C the viscosity coefficient of the solvent is 5 75 cP Diffusion coefficients of A B and P are 5 28 3 86 and 9 23 cm s respectively please calculate the rate constant of this reaction in dm mol s

The activation energy of the reaction A B C D 38 kcal is 20 kcal What would be the activation energy of the following reactio C D A B 1 20 kcal 2 20 kcal 3 18 kcal

calculate the packing fraction of BCC unit cell Half life of a first order reaction at a given temperature is a 3 min Calculate the time required for the completion of 3 4 th of the reaction a 12 min b 6 min c 24 min d 20 min mothoxymothon c HI

Data for the dimerization 2A A of a certain nitrile oxide compound A in ethanol solution at 40 C follow A mmol dm 68 0 50 2 40 3 33 1 28 4 22 3 18 7 t min 0 40 80 120 160 240 300 Find the reaction order using the half life method 14 5 420

A 2 97L sample of gaseous HI having density of 12 619 g L is heated to 641 6F As time passes the HI decomposes to gaseous H and 12 The rate law at thi temperature is given by k 0 031 M min What is the partial pressure of H after a reaction time of 6 01h Record your answer in atm with 3 decimals

de Broglie wavelength in metre of a microscopic particle of 2 mg mass moving with speed of 3 3 m s will be Planck s constant h 6 6 10 34 Js Only One Correct Answer A 10 26 8 10 29 C

Time and concentration data were collected for the reaction A products 0 20 40 60 80 100 A M 0 52 0 43 0 35 0 29 0 23 0 19 The blue curve is the plot of the data The straight orange line is tangent to the blue curve at t 40 s Approximate the instantaneous rate of this reaction at time t 40 s instantaneous rate M s 0 52 0 48 0 44 0 40 0 36 0 32 0 28 0 24 0 20 0 16 0 10 20 30 40 50 60 70 80 90 t s

In cv y 0 03212 slope 1st order time min 0 03212 x 10 85 units Kun I in cv in cv y 0 0 2348 slope 234 8 2nd order time min X 4 397x10 units

a For the following consecutive reaction if k k2 prove that the rate of the reaction depends on the step 2 assume the reactions follow first order kinetics k k step 1 step 2 b What is temperature coefficient for a reaction X Y Z

Question 4 of 36 Time and concentration data were collected for the reaction A products t s 0 20 40 60 80 100 A M 0 52 0 43 0 35 0 29 0 23 0 19 The blue curve is the plot of the data The straight orange line is tangent to the blue curve at t 40 s Approximate the instantaneous rate of this reaction at time t 40 s instantaneous rate 0 00875 M S 0 52 0 48 0 44 0 40 0 36 0 32 0 28 0 24 0 20 0 16 0 10 20 30 40 50 60 70 t s At

McQuarrie Rock Gallogly Consider the initial rate data at a certain temperature in the table for the reaction described by 2 NO g O g N O g O g Determine the value and units of the rate constant k k 2 99 X104 Incorrect NO2 o M 0 650 1 10 1 76 Units presented by Macmillan Learning 03 o M 0 800 0 800 1 40 M 5 1 Initial rate M s 2 99 104 5 06 x 104 14 17 x 104

5 7 m sec mid way between the two directions 4 5 m sec at an angle off tan 4 3 with the directions of intial velocity v J VEIXY 4 The width of the 3 4 Raftan 4 3 5 m s 20m s at an ang VC 168 4 time to cross the 130 A man A is sitting in the rear end of a long compartment of 130 A crusta 1 2 s 2 a train running at constant horizontal velocity tosses a coin to a person B near the front end of the compartment The trajectory of the coin is as seen by B and a person C on the ground will have 1 different vertical ranges but equal horizontal ranges 2 equal horizontal and equal vertical ranges 3 equal vertical ranges but different horizontal ranges 4 different vertical and different horizontal ranges 1 Three ships A Band Care in motion The mati B THE 1 2 3 4 er en B 1 CR Fe TECHE BIGG DIH A 2 3 2 3 4 Data not su A particle is pr Cits horizontal other extremit the triangle

For the two first order rea terms of temperature are given below AP K 1015 e BQ K 1014 e 1 217 C 3 500 C 1500 T 1000 T If initially t 0 both reaction started with same initial concentration of A and B then at what temperature both the reaction will have same initial rate NCERT Pg 112 2 217 K 4 500 K

a 4 b 8 5 The rate of a first order reaction is 0 04 mol L s at 10 sec and 0 03 mol L s at 20 sec after initiation of the reaction The half life period of the reaction is a 34 1 s b 44 1 s c 54 1 s d 24 1 s

10 of 36 Using the data in the table calculate the rate constant of this reaction k A BC D Trial A M 1 2 3 Units 0 360 0 360 0 432 B M 0 200 0 440 0 200 Rate 0 0 0 1 0 02

ion 24 of 36 Consider the reaction data What two points should be plotted to graphically determine the activation energy of this reaction To avoid rounding erre at least three significant figures in all values x1 A products T K k S 325 0 378 625 0 899 x2 y1 y2 Determine the rise run and slope of the line formed by these points

Question 3 of 36 Determine the average rate of change of B from t 0 s to t 302 s A2B rate 0 00315 Incorrect M S Time s 0 151 302 Concentration of A M 0 740 0 450 0 160

Question 9 of 36 Using the data in the table determine the rate constant of the reaction and select the appropriate units A 2BC D k Trial A M B M Rate M s 1 0 300 0 600 0 300 2 3 Units 0 220 0 220 0 440 0 0162 0 0162 0 0648

Using the data in the table calculate the rate constant of this reaction k A B C D 1 404 Incorrect Trial 1 2 3 Units A M B M 0 360 0 200 0 360 0 440 0 432 0 200 M S 1 Rate M s 0 0230 0 111 0 0276

Which among the following is a first order reaction 2 NH3 g N O g 2H O 1130K Pt catalyst N g 3 H g 2NO g 1 0 g 1 alkaline medium hr m 2H O O 2 NO g O g 2 NO g

9 10pts Following figures depict changes in various physical properties during a physical transformation Determine whether this physical transformation is the 1st order or the 2nd order phase transition Explain your answer Volume V Enthalpy H Chemical potential Entropy S Heat capacity C

For A g 3B g 2C g If initial pressure of A Po and after time t from the start of reaction th total pressure is p then the rate constant reaction is given by NCERT Pg 10 1 In 2 the In po 5p 4p 4p 3 In p 5p

4 m A buffer solution is prepared in which the concentration of NH3 is 0 30 M and the concentration of NH4 is 0 20 M If the equilibrium constant K for NH3 equals 1 8 105 what i the pH of this solution log 2 7 0 43 3 11 72 2 9 43 1 9 08 4 8 73 potentials for

0 The specific conductance of saturated solution a CaF is 3 86 x 10 5 mho cm and that of wate used for solution is 0 15 x 10 5 The specifi conductance of CaF alone is 2 1 3 71 x 10 5 2 4 01 x 10 5 3 3 7 x 10 4 4 3 86 x 104

A 118 Cd Radionuclide goes through the transformation chain 118 Cd Cd 1 2 30min 118 In t1 2 45 min 118 Sn stable At time t 0 only Cd was present find the fraction of nuclei transformed into stable over 90 minutes

AgCl is crystallized from molten AgCl containing a little Cd Cl2 The solid obtained will have anionic vacancies neither cationic nor anionic vacancies cationic vacancies equal to double the number of Cd2 ion S cationic vacancies equal to a number of Cd2 ions incorpo rated

For first A g 3B g 2C g If initial pressure of A Po and after time t from the start of reaction th total pressure is p then the rate constant reaction is given by NCERT Pg 100 1 In STRAGE 2 In 3 the In p p p 5p 4p 4p p 5p

The rate constant the activation energy and Arrhenius parameter of a chemical reaction at 25 C are x 10x kJ mol and 2x s 1 Value of rate constant as T is 1 X S 1 2 2x s 1 K A e dt 3 4 10x s 1 8

The rate constant k of a reaction is found to be double that of rate constant k of another reaction The relationship between corresponding activation energies of the two reactions at same temperature E E can be represented as 1 E E 3 E E 2 E E 4 E 4E

Pre Medical Chemistry 255 156 If H O H O AH 68 39 kCal K H O water AH 48 0 kCal KOH aq 2 H KOH water KOH aq AH 14 0 kCal the heat of formation of KOH is 1 68 39 48 14 0 2 68 39 48 0 14 0 3 68 39 48 0 14 0

The reaction A B follows second order kinetics At 30 C the half life for the decomposition of A is 7 hours when the initial concentration of A is 4 46 M At 90 C the energy of activation of the reaction is 200 kJ mol Calculate the rate constant of this reaction at 30 C 4 1 2

2 Concentration of the product 3 Volume of the reaction container 4 Temperature CK0105 For the decomposition of N O g it is given that 2N O g 4NO g O g activation energy E N O g 2NO g O g activation energy E then 1 E 2E 3 E E 2 E E 4 E E

Rate of the reaction in terms of the pressure of the reactant assume rate as an extensive property is CH CHO CO CH 1 3 VdPCH CHO RT dt dPCH CHO 1 RTV dt 2 4 1 dpCH CHO RT dt nCH CHo dpCH CHO V dt

Pre Medical Chemistry 65 0 The rate constant the activation energy and the Frequency factor of a chemical reaction at 25 C are 3 x 10 s 104 4 kJ mol and 6 0 x 10 4 respectively the value of the rate constant as Tis 1 2 x 10 S 3 Infinity 2 6 x 10 4 4 3 6 x 100 CK0099

141 From the reactions C s 2H g CH g AH X Kcal C g 4H g CH g AH X Kcal CH g CH g H g AH Y Kcal Bond energy of C H bond is 1 kCal mol 3 kCal mol 4 2 Y kCal mol 4 X kCal mol

3 Thermal decomposition of HCOOH is a first order reaction and the rate constant at T K is 4 606 x 10 s The time required to decompose 90 of initial quantity of HCOOH at T K in second is A 100 B 500 C 1000 D 50