Chemical Reaction Engineering And Reactor Design

2.

Which of the following is not a unit of reaction rate?

Moles formed/(surface of catalyst) (time)
Moles formed/(volume of reactor) (time)
Mole formed/(volume of catalyst) (time)
None of these

Correct Answer

A. None of these

Explanation

All of the options listed are valid units of reaction rate. Each option represents a different way to express the rate of a reaction in terms of the moles formed and the corresponding unit of measurement (surface area of catalyst, volume of reactor, or volume of catalyst) divided by time. Therefore, the correct answer is "none of these" as all the options are units of reaction rate.

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3.

If “n” is the order of reaction then unit of rate constant is

(a) 1 (time) (concentration 1/(time) (concentration)^n-1
(time)-1(concentration)n-1
(time)n-1 (concentration)
None of these

Correct Answer

A. (a) 1 (time) (concentration 1/(time) (concentration)^n-1

Explanation

The unit of the rate constant depends on the order of the reaction. In this case, the answer (a) 1 indicates that the unit of the rate constant is simply 1, which means it is dimensionless. This implies that the rate constant does not have any specific unit and is independent of time or concentration.

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4.

Which of the following is a controlling factor in very fast heterogeneous reaction?

Heat and mass transfer effects
Pressure
Temperature
Composition of reactant

Correct Answer

A. Heat and mass transfer effects

Explanation

Heat and mass transfer effects are controlling factors in very fast and heterogeneous reactions. In these types of reactions, the rate of reaction is influenced by the transfer of heat and mass between the reactants. The efficiency of heat and mass transfer can affect the reaction rate by determining the availability and accessibility of reactant molecules. If heat and mass transfer are not efficient, the reactant molecules may not be able to come into contact with each other effectively, resulting in a slower reaction rate. Therefore, heat and mass transfer effects play a crucial role in controlling the speed of very fast and heterogeneous reactions.

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5.

Variables affecting the rate of homogeneous reactions are

Pressure and temperature only
Temperature and composition only
Pressure and composition only
Pressure, temperature and composition

Correct Answer

A. Pressure, temperature and composition

Explanation

The rate of homogeneous reactions is affected by pressure, temperature, and composition. Pressure affects the rate by influencing the collision frequency and the number of effective collisions between reactant molecules. Temperature affects the rate by increasing the kinetic energy of the molecules, leading to more frequent and energetic collisions. Composition, specifically the concentration of reactants, affects the rate by determining the number of collisions and the likelihood of successful collisions. Therefore, all three variables play a role in determining the rate of homogeneous reactions.

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6.

Rate determining step in a reaction consisting of a number of step in series is the

Fastest step
Slowed step
Intermediate step
Data insufficient; can't be predict

Correct Answer

A. Slowed step

Explanation

In a reaction consisting of multiple steps in series, the rate-determining step is the slowest step. This means that the overall rate of the reaction is determined by the speed at which this particular step occurs. The other steps may happen more quickly, but they do not significantly affect the overall rate of the reaction. Therefore, the slowed step is the correct answer.

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7.

Chemical kinetics can predict the

Rate of reaction
Feasibility of reaction
Both (a) and (b)
None of these

Correct Answer

A. Rate of reaction

Explanation

Chemical kinetics is the branch of chemistry that studies the rate at which chemical reactions occur. It involves the measurement and analysis of reaction rates, as well as the factors that influence them. By studying the rate of reaction, chemical kinetics can provide insights into the mechanisms and dynamics of chemical reactions. It can also be used to predict the rate at which a reaction will occur under specific conditions. Therefore, the correct answer is "rate of reaction".

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8.

Velocity of a chemical reaction

Decreases with increase in temperature
Increases with increase of pressure of reactant for all reactions
Decreases with increase of reactant concentration
None of these

Correct Answer

A. None of these

9.

Sum of the powers of the concentration terms in the rate equation is called the

Order of the reaction
Overall order of the reaction
Molecularity of the reaction
None of these

Correct Answer

A. Overall order of the reaction

Explanation

The overall order of the reaction refers to the sum of the powers of the concentration terms in the rate equation. This means that the overall order of the reaction is determined by adding up the exponents of the concentration terms in the rate equation. Therefore, the correct answer is "overall order of the reaction."

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10.

Molecularity of a reaction

Is always equal to the overall order of reaction
May not be equal to the order of reaction
Can’t have a fractional value
Both b and c

Correct Answer

A. Both b and c

Explanation

The molecularity of a reaction refers to the number of molecules that participate as reactants in a single step of the reaction. The overall order of reaction, on the other hand, refers to the sum of the powers to which the concentration terms are raised in the rate equation. These two terms are not always equal to each other. Additionally, the molecularity of a reaction cannot have a fractional value, as it represents the number of molecules involved in a single step. Therefore, the correct answer is both b and c.

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Chemical Reaction Engineering And Reactor Design

Rate of chemical reaction is independent of the concentration of reactants for

Quiz Preview

Which of the following is not a unit of reaction rate?

If “n” is the order of reaction then unit of rate constant is

Which of the following is a controlling factor in very fast heterogeneous reaction?

Variables affecting the rate of homogeneous reactions are

Rate determining step in a reaction consisting of a number of step in series is the

Chemical kinetics can predict the

Velocity of a chemical reaction

Sum of the powers of the concentration terms in the rate equation is called the

Molecularity of a reaction