Q: For a reaction $$A \rightarrow P$$, if the initial concentration of $$A is 2 $$mol/L and $$k = 1.5 \times 10^2$ \ s$$^{-1}$$, what is the initial rate of disappearance of A$ for a first-order reaction?

$$3.0 \times 10^2$ \ mol \cdot L$$^{-1}$$ \cdot s$$^{-1}$$

Question 1

Which factor does NOT directly affect the rate of a chemical reaction according to collision theory?

Accepted Answer

Color of the reactants

Question 2

For the reaction $$A + 2B \rightarrow 3P + Q$$, what is the correct expression for the rate of disappearance of B?

Accepted Answer

$$r = -2 \frac{d[B]}{dt}$$

Question 3

A batch reactor is stopped before complete conversion of reactants. What is the main reason for this in industrial practice?

Accepted Answer

Because the reaction rate becomes too slow as reactant concentration decreases

Question 4

Given the rate law $$rate = k[A]^x[B]^y$$, what is the overall order of the reaction?

Accepted Answer

$$x + y$$

Question 5

Which of the following statements about catalysts is TRUE?

Accepted Answer

Catalysts lower the activation energy, increasing the reaction rate

Question 6

For a zero-order reaction, what is the correct unit for the rate constant $$k$$?

Accepted Answer

$$mol \cdot L$$^{-1}$$ \cdot s$$^{-1}$$

Question 7

Which reactor type is best described as having a continuous flow of reactants and products, with no mixing in the direction of flow?

Accepted Answer

Plug flow reactor (PFR)

Question 8

In the Michaelis-Menten model for enzyme kinetics, what does the parameter $$K_m$$ represent?

Accepted Answer

The substrate concentration at which the reaction rate is half its maximum

Question 9

A reaction is found to be first order in A and zero order in B. What is the correct rate law?

Accepted Answer

$$rate = k[A]$$

Question 10

Which statement best describes the effect of increasing temperature on the rate constant $$k$$?

Accepted Answer

The rate constant $$k$$ increases

Question 11

For the reaction $$A + B \rightarrow C$$, the initial rate method gives the following data: doubling $$[A]$$ doubles the rate, doubling $$[B]$$ quadruples the rate. What is the correct rate law?

Accepted Answer

$$rate = k[A][B]^2$$

Question 12

In a biological system, the Monod model describes microbial growth as $$\mu = \frac{\mu_{max} S}{K_s + S}. $$What happens to the growth rate $$\mu as $$substrate concentration $$S$$ becomes very large?

Accepted Answer

$$\mu$$ approaches $$\mu_{max}$$

Question 13

Which of the following is a correct statement about the stoichiometric coefficients in a reaction rate expression?

Accepted Answer

They are negative for reactants and positive for products

Question 14

In a reaction mechanism, which step determines the overall reaction rate?

Accepted Answer

The slowest step

Question 15

For a reaction $$A ightarrow P$$, if the initial concentration of $$A is 2 $$mol/L and $$k = 1.5 	imes 10^2$ \ s$$^{-1}$$, what is the initial rate of disappearance of A$ for a first-order reaction?

Accepted Answer

$$3.0 	imes 10^2$ \ mol \cdot L$$^{-1}$$ \cdot s$$^{-1}$$

Question 16

Which of the following best explains why the concentration of reactants decreases exponentially over time in a first-order reaction?

Accepted Answer

Because the rate is proportional to the concentration

Question 17

In a reaction with autokatalysis, what is the effect of the product on the reaction rate?

Accepted Answer

The product increases the reaction rate

Question 18

Which of the following is TRUE about the equilibrium constant $$K_{eq}$$ for a reversible reaction?

Accepted Answer

It is equal to the ratio of the forward and reverse rate constants

Question 19

For a bimolecular elementary reaction $$A + B \rightarrow products$$, what is the correct rate law?

Accepted Answer

$$rate = k[A][B]$$

Question 20

In a real-world scenario, two genetically engineered bacteria are used for pollution cleanup. Organism A has $$\mu_{max} = 1 \ d$$^{-1}$$ and K_s = 0.1$$ \ mg/L$$, while organism B has $$\mu_{max} = 5 \ $$d^{-1}$$ and $$K_s = 5 \ mg/L. $$Which organism is more effective at reducing pollutant to trace levels?

Accepted Answer

Organism A

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