A. Is same as heat of reaction at constant pressure
B. Is the minimum energy which the molecules must have before the reaction can take place
C. Varies as fifth power of the temperature
D. Both B. and C.
Related Mcqs:
- The rate expression for a heterogeneous catalytic reaction is given by, – rA = K.KA PA(1 + KA.PA + KR.PR), where K is surface reaction rate constant and KA and KR are absorption equilibrium constants of A and R respectively. If KR PR >> (1 + KA PA), the apparent activation energy EA is equal to (given E is the activation energy for the reaction and ΔHR and ΔHA are the activation energies of adsorption of R and A) ?
A. E
B. E + ΔHA
C. E + ΔHA – ΔHR)
D. ΔHA + ΔHR - The minimum energy required to allow a chemical reaction to proceed is termed as the ‘threshold energy ‘. Chemical reactions with low activation energy are ________________?
A. Always irreversible
B. Insensitive to temperature changes
C. Mostly irreversible
D. Highly temperature sensitive - A chemical reaction occurs, when the energy of the reacting molecules is ________________ the activation energy of reaction?
A. Less than
B. Equal to
C. More than
D. Equal to or more than - A chemical reaction occurs when the energy of the reacting molecules is __________________ the activation energy of the reaction?
A. Less than
B. Equal to
C. More than
D. Equal to or more than - Rate constant for a first order reaction does not depend upon reaction time, extent of reaction and the initial concentration of reactants; but it is a function of reaction temperature. In a chemical reaction, the time required to reduce the concentration of reactant from 100 gm moles/litre to 50 gm moles/litre is same as that required to reduce it from 2 gm moles/litre to 1 gm mole/litre in the same volume. Then the order of this reaction is ?
A. 0
B. 1
C. 2
D. 3 - For the chemical reaction P → Q, it is found that the rate of reaction doubles as the concentration of ‘P’ is doubled. If the reaction rate is proportional to Cp n, then what is the value of ‘n’ for this chemical reaction ?
A. 0
B. 1
C. 2
D. 3 - In a reaction, the threshold energy is equal to (where, A = activation energy N = normal energy of reactants) ?
A. A
B. N
C. A + N
D. A – N - Higher free energy of activation of a chemical reaction (at a given temperature) implies ____________________?
A. Slower rate of reaction
B. Higher rate of reaction
C. Higher equilibrium conversion
D. Both B. and C. - Enzymes (a protein) are catalysts found in organisms. Its efficiency of catalysing a reaction is due to its capacity to lower the activation energy of the reaction. The enzyme ptyalin used for food digestion is present in ___________________?
A. Blood
B. Saliva
C. Intestine
D. Gland - In a chemical reaction, represented by as shown in the bellow figure, it is observed that the (i) Rate of reaction increases by a factor of 4 on doubling the concentration of the reactant. (ii) Rate of reaction increases by a factor of 9 on trebling the concentration of the reactant. Then the rate of the reaction is proportional to(where, CA = concentration of the reactant)_____________________?
A. CA
B. CA2
C. CA3
D. CA4
