Enzymes increase the rates of reactions by (A) Increasing the free energy of activation (B) Decreasing the energy of activation (C) Changing the equilibrium constant of the reaction (D) Increasing the free energy change of the reaction

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Answer :  B

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Description : Enzymes increases the rate of reactions by (A) Increasing the free energy of activation (B) Decreasing the energy of activation (C) Changing the equilibrium constant of the reaction (D) Increasing the free energy change of the reaction

Last Answer : Answer : B

Description : Enzymes accelerate the rate of reactions by (A) Increasing the equilibrium constant of reactions (B) Increasing the energy of activation (C) Decreasing the energy of activation (D) Decreasing the free energy change of the reaction

Last Answer : Answer : C

Description : Which one of the following statements regarding a catalyst is not correct? A An enzyme is a catalyst that only binds certain substrates. B An enzyme is a protein that is a highly ... increasing the activation energy. D Catalysts do not alter the equilibrium constant for a chemical reaction.

Last Answer : C Catalysts increase the rate of a reaction by altering the mechanism, thereby increasing the activation energy.

Description : Pick out the wrong statement. (A) Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value & chemical agents, is maximum at a temperature of about 45°C ... in enzyme catalysed reactions can be calculated by using the thermodynamic properties of substrates & prod

Last Answer : (C) Enzymes help in increasing the activation energy of the reaction

Description : An enzyme promotes a chemical reaction by (A) Lowering the energy of activation (B) Causing the release of heat which acts as a primer (C) Increasing molecular motion (D) Changing the free energy difference between substrate and product

Last Answer : Answer : A

Description : Pick out the correct statement. (A) Reactions with high activation energies are very temperature sensitive (B) Chemical equilibrium is a static state (C) A photochemical reaction is catalysed by ... occurs when the energy of the reacting molecule is less than the activation energy of the reaction

Last Answer : (A) Reactions with high activation energies are very temperature sensitive (B) Chemical equilibrium is a static state

Description : The role of a catalyst in a chemical reaction is to change the (A) Equilibrium constant (B) Activation energy (C) Final products (D) Heat of reaction

Last Answer : (B) Activation energy

Description : Catalytic action in a catalytic chemical reaction follows from the ability of catalyst to change the (A) Activation energy (B) Equilibrium constant (C) Heat of reaction (D) None of these

Last Answer : (A) Activation energy

Description : The function of an enzyme is to (A) Cause chemical reactions that would not otherwise take place (B) Change the rates of chemical reactions (C) Control the equilibrium points of reactions (D) Change the directions of reactions

Last Answer : Answer : B

Description : Object is in equilibrium if resultant force acting on it is A. increasing B. decreasing C. zero D. becomes constant

Last Answer : zero

Description : Pick out the wrong statement. (A) A particular chemical reaction is more temperature sensitive at low temperatures (B) A very high value of equilibrium constant, K (K >> 1) indicates that the ... ) Non-ideal flow takes place in reactors due to recycling, channeling or by creation of stagnant regions

Last Answer : (C) The intercept of the Arrhenius plot is called the 'activation energy

Description : The catalyst in a first order chemical reaction changes the (A) Equilibrium constant (B) Activation energy (C) Heat of formation of the product (D) Heat of reaction

Last Answer : (B) Activation energy

Description : 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 ... R and A) (A) E (B) E + ΔHA (C) E + ΔHA - ΔHR ) (D) ΔHA + ΔHR

Last Answer : (C) E + ΔHA - ΔHR )

Description : Pick out the wrong statement. (A) Visible radiation provides the necessary activation energy in photochemical reactions (B) The order and molecularity of a complex reaction may not be the same (C) For ... rate constant (k) (D) Molecularity of the reaction is always a whole number greater than zero

Last Answer : (B) The order and molecularity of a complex reaction may not be the same

Description : The total energy of each particle at various places in the case of perfect incompressible fluid flowing in continuous stream (A) Keeps on increasing (B) Keeps on decreasing (C) Remain constant (D) May increase/decrease

Last Answer : Answer: Option C

Description : 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)

Last Answer : (A) Slower rate of reaction

Description : Pick out the wrong statement. (A) Use of different catalysts in a reversible catalytic chemical reaction does not change the equilibrium composition (B) Alumina is added as a promoter to ... Arrhenius plot (D) Presence of inerts affects the equilibrium conversion of reactants in a chemical reaction

Last Answer : (C) Activation energy for a reaction is obtained from the intercept of the Arrhenius plot

Description : Pick out the correct statement. (A) A catalyst does not change AH of the reaction (B) A catalyst changes the equilibrium point (C) Law of mass action was suggested by Le-Chatelier (D) The difference between the energy of reactants and that of the products is the activation energy

Last Answer : (A) A catalyst does not change AH of the reaction

Description : Pick out the correct statement. (A) A chemical reaction accompanied by absorption of heat is called an exothermic reaction (B) A chemical reaction accompanied by evolution of heat is called an ... does not change on changing the concentration units (D) Chemical equilibrium state is dynamic in nature

Last Answer : (C) The rate constant for a first order reaction does not change on changing the concentration units

Description : Isoenzymes can be characterized by (A) Proteins lacking enzymatic activity that are necessary for the activation of enzymes (B) Proteolytic enzymes activated by hydrolysis (C) Enzymes with identical primary structure (D) Similar enzymes that catalyse different reaction

Last Answer : Answer : B

Description : Walter’s Model suggests that a firm can always increase the value of the share by: A. Increasing dividend B. Decreasing dividend C. Constant Dividend D. None of the

Last Answer : D. None of the

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Last Answer : raising the temp and lowering the temp

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Last Answer : C. Changing the sales mix

Description : A reduction in the number of producers will result in equilibrium price (a) increasing and quantity increasing ; (b) increasing and quantity decreasing ; (c) decreasing and quantity increasing ; (d) decreasing and quantity decreasing

Last Answer : (b) increasing and quantity decreasing ;

Description : A shift outward in supply curve will result in equilibrium price (a) increasing and quantity increasing ; (b) increasing and quantity decreasing ; (c) decreasing and quantity increasing ; (d) decreasing and quantity decreasing

Last Answer : (c) decreasing and quantity increasing ;

Description : A catalyst is a substance which (a) Changes the equilibrium of a reaction so that the concentration of the product increases (b) Increases the rate of reaction and increases the equilibrium concentration of products (c) Hastens the attainment of equilibrium (d) Increases the activation energy

Last Answer : Ans:(c)

Description : What happens when a catalyst is added to a system at equilibrium? A The reaction follows an alternative pathway of lower activation energy. B The heat of reaction decreases. C The potential ... decreases. D The potential energy of the products decreases. E The rate of chemical reaction decreases.

Last Answer : A The reaction follows an alternative pathway of lower activation energy.

Description : The catalytic power of enzymes is due to (a) the presence of amino acids in their structures (b) their high molecular weight (c) their ability to lower the activation energy of the reaction (d) their limited solubility in water and other solvents

Last Answer : Ans:(c)

Description : 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

Last Answer : (B) Saliva

Description : Role of an enzyme in reactions is to/as (a) decrease activation energy (b) increase activation energy (c) inorganic catalyst (d) none of the above.

Last Answer : (a) decrease activation energy

Description : Pick out the wrong statement. (A) In a multistep reaction, the slowest step is the rate determining step (B) In general, the rate of a reaction becomes triple for every 10°C rise in temperature (C ... energy (D) Molecularity of a reaction cannot be zero but the order of a reaction can be zero

Last Answer : (B) In general, the rate of a reaction becomes triple for every 10°C rise in temperature

Description : Pick out the wrong statement: (A) Chemical reactions with high activation energy are very temperature sensitive (B) A flat velocity profile exists in a plug flow reactor (C) The residence ... D) Half life of a reaction increases with increased initial concentration for reaction orders more than one

Last Answer : (C) The residence time for all the elements of fluid in case of a P.F.R. need not be same

Description : 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

Last Answer : (B) Insensitive to temperature changes

Description : Pick out the correct statement. (A) In catalytic reactions, the catalyst reacts with the reactants (B) A catalyst initiates a chemical reaction (C) A catalyst lowers the activation energy of ... molecules (D) A catalyst cannot be recovered chemically unchanged at the end of the chemical reaction

Last Answer : (C) A catalyst lowers the activation energy of the reacting molecules

Description : The space time is equivalent to the holding time in a steady state mixed reactor for (A) Non-isothermal gas reaction (B) Variable fluid density systems (C) Constant fluid density systems (D) Gas reactions with changing number of moles

Last Answer : (C) Constant fluid density systems

Description : If the rate of a chemical reaction becomes slower at a given temperature, then the (A) Initial concentration of the reactants remains constant (B) Free energy of activation is lower (C) Entropy changes (D) Free energy of activation is higher

Last Answer : (D) Free energy of activation is higher

Description : An enzyme brings about (A) Decrease in reaction time (B) Increase in reaction time (C) Increase in activation energy (D) Reduction in activation energy

Last Answer : Answer : D

Description : Identify the INCORRECT statement below regarding chemical equilibrium. A All chemical reactions are, in principle, reversible. B Equilibrium is achieved when the forward reaction rate equals the ... equilibrium constant. E Equilibrium is achieved when reactant and product concentrations are equal.

Last Answer : E Equilibrium is achieved when reactant and product concentrations are equal.

Description : During inter conversion of energy from one form to other forms, total energy at any time remains– (1) constant (2) zero (3) increasing (4) decreasing

Last Answer : (1) constant Explanation: During interconversion of energy from one form to other forms, total energy at any time remains constant.

Description : During size reduction by a jaw crusher, the energy consumed decreases with the (A) Decreasing size of product at constant size of feed (B) Decreasing machine capacity (C) Increasing size of feed at constant reduction ratio (D) None of these

Last Answer : (C) Increasing size of feed at constant reduction ratio

Description : The free energy change for a chemical reaction is given by (where, K = equilibrium constant) (A) RT ln K (B) -RT ln K (C) -R ln K (D) T ln K

Last Answer : (B) -RT ln K

Description : In which of the following reactions, standard reaction entropy change (S°) is positive and standard Gibb's energy change (G°) decreases sharply with increasing temperature? (1) 2 2 1 1 1 C graphite O (g) CO (g) 2 2 2   (2) 2 1 C ... CO(g) O (g) CO (g) 2   (4) 2 1 Mg(s) O (g) MgO(s) 2  

Last Answer : C graphite O (g) CO(g)

Description : When Increasing the concentration and increasing the temp both increase the reaction rates based on which physical phenomenon?

Last Answer : The kinetic energy of the reactants. By increasing the concentration, there are more reactant particles available for the reaction, and increasing the temperature increases the kinetic energy so the reactants come in contact more often, and the reaction rate increases.

Description : Template/lock and key theory of enzyme action is supported by (A) Enzymes speed up reaction (B) Enzymes occur in living beings and speed up certain reactions (C) Enzymes determine the direction of reaction (D) Compounds similar to substrate inhibit enzyme activity

Last Answer : Answer : D

Description : Arrhenius equation K = Ae-E a / R T In some reactions, Rate of reaction is directly proportional to. Concentration of catalyst Catalyst used in Bio-Chemical reactions is called. Enzymes Reactions catalyzed by light are called as. Photo catalyzed or Photosensitised reactions

Last Answer : Define order of reaction

Description : The increasing vapor pressure caused by heating a liquid is due to------? A. increase inter-molecular interactions B. increasing potential energy of molecules C. increasing kinetic energy of molecules (Answer) D. decreasing surface tension

Last Answer : C. increasing kinetic energy of molecules (Answer)

Description : In the illustrated amplifier, the RESET potentiometer A1R2 sets the stability of the control loop by changing the reset time constant. As the potentiometer is turned clockwise _________. EL-0060 A. ... is increased to the summing point at terminal 5 D. response time is increased decreasing stability

Last Answer : Answer: B

Description : Acute pancreatitis is characterised by (A) Lack of synthesis of zymogen enzymes (B) Continuous release of zymogen enzymes into the gut (C) Premature activation of zymogen enzymes (D) Inactivation of zymogen enzymes

Last Answer : Answer : C

Description : Activation or inactivation of certain key regulatory enzymes is accomplished by covalent modification of the amino acid: (A) Tyrosine (B) Phenylalanine (C) Lysine (D) Serine

Last Answer : Answer : D

Description : If a coenzyme is required in an enzyme reaction, the former usually has the function of (A) Acting as an acceptor for one of the cleavage products of the substrate (B) Enhancing the specificity ... C) Increasing the number of receptor sites of the apo enzyme (D) Activating the substrate ENZYMES 167

Last Answer : Answer : A