Chemistry - Rates of Chemical Reactions and Chemical Kinetics

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Question - 1

When spherical particles of 0.1 mm diameter are ground to spherical particles of 0.025 mm diameter (for the same volume), the surface area increase to 

  • A 4 times
  • B 8 times
  • C 16 times
  • D 32 times

Question - 2

For a first order reaction k=5.48 x10-4s-1. The two-third life for this reaction wound be

  • A 2005 s
  • B 1000 s
  • C 2000 s
  • D 3005 s

Question - 3

A reaction is of first order with respect to reactant A, has a rate constant 6 min-1. If one starts with [A]= 0.5 mol L-1, the concentraction of [A] would reach to 0.05 mol L-1 in

  • A 20 s
  • B 21 s
  • C 22 s
  • D 23 s

Question - 4

If the rate constant of a reaction is 2.0 mol-1 L-1 at 700 K and 32 mol-1 L s-1 at 800 K the activation energy for the reaction is

  • A 120.11 kJ mol-1
  • B 127.11 kJ mol-1
  • C 129.11 kJ mol-1
  • D 130.11 kJ mol-1

Question - 5

The rate of a particular reaction quadruples, when the temperature chages from 293 K to 313 K. The  activation energy for such reaction would be

  • A 50.855 kJ mol-1
  • B 52.855 kJ mol-1
  • C 54.855 kJ mol-1
  • D 56.855 kJ mol-1

Question - 6

Which of the following best explains how catalysts increase the rate of a chemical reaction?

  • A They reduce the amount of product 
  • B They increase the amount of the product
  • C They reduce the amount of reactants
  • D They reduce the activation energy for the recation

Question - 7

Choose the correct statement from the following :

  • A The addition of catalyst changes equillibrium constant
  • B A catalyst speeds up the forward reaction. and slows down the backward reaction
  • C The composition of the equillibrium mixture is not changed by a catalyst.
  • D A catalyst is active only in solution

Question - 8

When concentractions are expressed in mole units and time in seconds, the units of the zero order rate constant (k) are

  • A mol L-1 s-1
  • B L mol-1 s-1
  • C s-1
  • D L2 mol-2 s-1

Question - 9

Which one of the following statements is wrong in case of enzyme catalysis?

  • A Enzymes work best at an optimum temperature
  • B Enzymes work at optimum pH value
  • C Enzymes are highly specific for substrates
  • D Enzyme raises activation energy

Question - 10

A reaction that is of first order with respect to reactant A has a rate constant 6 mim-1. If we start with [A] = 0.5 mol L-1, when would [A] reach the value 0.05 mol L-1?

  • A 3.84 min
  • B 3 min
  • C 0.15 min
  • D 0.384 min