Rates of Chemical Reactions

What is the unit of the rate constant (kr) in the given reaction?

cm^3 mol^-1 s^-1
cm^3 molecule^-1 s^-1
dm^3 molecule^-1 s^-1
dm^3 mol^-1 s^-1 (correct)

What is the value of the rate constant (kr) in the given reaction?

4.8 × 10^5 dm^3 mol^-1 s^-1 (correct)
8.0 × 10^-18 dm^3 molecule^-1 s^-1
2.0 × 10^-10 dm^3 mol^-1 s^-1
8.0 × 10^-15 cm^3 molecule^-1 s^-1

What is the significance of knowing the rate law of a reaction?

It helps in understanding the mechanism of the reaction
It helps in predicting the rate of reaction from the composition of the mixture
It helps in understanding the kinetics of the reaction
All of the above (correct)

What is the advantage of knowing the value of the rate constant?

It helps in predicting the composition of the reaction mixture at a later stage (B) Signup and view all the answers

What is the expression for the rate of reaction in terms of the formation of Br2?

d[Br2]/dt = 0.080 mmol dm^-3s^-1 (D) Signup and view all the answers

What is the unit of rate constant kr when the concentrations are expressed in mol dm⁻³?

mol² dm⁻¶ s⁻¹ (D) Signup and view all the answers

What is the overall order of the reaction with a rate law v = k [A]²[B]?

Third order (C) Signup and view all the answers

What is the expression for the rate of consumption of NOBr?

-d[NOBr]/dt (D) Signup and view all the answers

What is the unit of the rate of reaction v when the concentrations are expressed in mol dm⁻³ and the rate constant kr is in mol² dm⁻¶ s⁻¹?

mol dm⁻³ s⁻¹ (D) Signup and view all the answers

What is the relationship between the rate of reaction v and the rate of change of concentration of a reactant?

v = d[reactant]/dt / ν (reactant) (A) Signup and view all the answers

What is the power to which the concentration of a reactant is raised in a rate law?

The order of reaction with respect to that reactant (D) Signup and view all the answers

What is the order of the reaction with respect to H2 in the rate law for the reaction H2(g) + Br2(g) → 2 HBr(g)?

First order (B) Signup and view all the answers

What is the characteristic of a zeroth-order rate law?

The rate is independent of the concentration of the reactant (C) Signup and view all the answers

What is the significance of the rate law v = kr in the decomposition of phosphine (PH3)?

The reaction is zeroth order with respect to PH3 (A) Signup and view all the answers

What is the purpose of identifying the rate law and obtaining the rate constant from experimental data?

To understand the reaction kinetics (D) Signup and view all the answers

What is the order of the reaction with respect to Br2 in the rate law for the reaction H2(g) + Br2(g) → 2 HBr(g)?

Indefinite order (A) Signup and view all the answers

Why is it important to experimentally determine the rate law for a reaction?

To determine the reaction kinetics (C) Signup and view all the answers

What is the significance of the rate law in the context of reaction kinetics?

It describes the reaction rate and its dependency on reactant concentrations (C) Signup and view all the answers

What is the relationship between the rate law and the reaction order?

The reaction order determines the rate law (B) Signup and view all the answers

What is the relationship between the most probable speed, c*, and the root mean square speed, c, of a molecule?

c* is always smaller than c (A) Signup and view all the answers

What is the effect of increasing the temperature on the Maxwell distribution of molecular speeds?

The distribution becomes broader and shifts to the right (D) Signup and view all the answers

What is the average speed of molecules in a gas, according to the Maxwell-Boltzmann distribution?

The mean speed, c̄ (D) Signup and view all the answers

What is the proportionality of the number of molecules at energy level E at temperature T?

proportional to exp(-E/kT) (C) Signup and view all the answers

What is the significance of the pre-exponential factor, v^2, in the Maxwell-Boltzmann distribution?

It determines the fraction of molecules at very low speeds (D) Signup and view all the answers

What is the relationship between the mean speed of two identical molecules, c̄, and the relative speed, c̄rel, at which they approach each other?

c̄rel is larger than c̄ (D) Signup and view all the answers

What is the normalization constant K in the Maxwell-Boltzmann distribution?

1 / (√(2πRT/M))³ (C) Signup and view all the answers

What is the distribution of speeds of molecules in a system at thermal equilibrium?

Maxwell distribution (A) Signup and view all the answers

What is the most probable speed of molecules in a system at thermal equilibrium?

Zero (B) Signup and view all the answers

What is the fraction of molecules that have speeds in a range of [v, v+dv] equal to?

f(v)dv (D) Signup and view all the answers

What is the unit of the collision frequency z?

s⁻¹ (A) Signup and view all the answers

What is the mean free path λ in a gas?

The average distance a molecule travels between collisions (A) Signup and view all the answers

What happens to the mean free path λ at constant volume when the temperature increases?

It remains the same (A) Signup and view all the answers

What is the relation between the collision frequency z and the pressure p?

z ∝ p (A) Signup and view all the answers

What is the value of the mean speed c̄rel for N₂ at 298 K and 100000 Pa?

475 m/s (B) Signup and view all the answers

What is the relationship between the root mean square speed of the molecules and the temperature?

It is proportional to the square root of the temperature (B) Signup and view all the answers

What is the difference between the root mean square speed and the average speed of the molecules?

The root mean square speed is always higher than the average speed (D) Signup and view all the answers

What is the expression for the root mean square speed of the molecules?

c = √(3RT/M) (C) Signup and view all the answers

What is the significance of the Maxwell-Boltzmann distribution?

It describes the distribution of speeds of molecules in a gas (B) Signup and view all the answers

What is the relationship between the molar mass of a gas and the root mean square speed of its molecules?

Heavier molecules have a lower root mean square speed (C) Signup and view all the answers