39 Questions
What is the unit of the rate constant (kr) in the given reaction?
dm^3 mol^-1 s^-1
What is the value of the rate constant (kr) in the given reaction?
4.8 × 10^5 dm^3 mol^-1 s^-1
What is the significance of knowing the rate law of a reaction?
All of the above
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
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
What is the unit of rate constant kr when the concentrations are expressed in mol dm⁻³?
mol² dm⁻¶ s⁻¹
What is the overall order of the reaction with a rate law v = k [A]²[B]?
Third order
What is the expression for the rate of consumption of NOBr?
-d[NOBr]/dt
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
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)
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
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
What is the characteristic of a zeroth-order rate law?
The rate is independent of the concentration of the reactant
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
What is the purpose of identifying the rate law and obtaining the rate constant from experimental data?
To understand the reaction kinetics
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
Why is it important to experimentally determine the rate law for a reaction?
To determine the reaction kinetics
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
What is the relationship between the rate law and the reaction order?
The reaction order determines the rate law
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
What is the effect of increasing the temperature on the Maxwell distribution of molecular speeds?
The distribution becomes broader and shifts to the right
What is the average speed of molecules in a gas, according to the Maxwell-Boltzmann distribution?
The mean speed, c̄
What is the proportionality of the number of molecules at energy level E at temperature T?
proportional to exp(-E/kT)
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
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
What is the normalization constant K in the Maxwell-Boltzmann distribution?
1 / (√(2πRT/M))³
What is the distribution of speeds of molecules in a system at thermal equilibrium?
Maxwell distribution
What is the most probable speed of molecules in a system at thermal equilibrium?
Zero
What is the fraction of molecules that have speeds in a range of [v, v+dv] equal to?
f(v)dv
What is the unit of the collision frequency z?
s⁻¹
What is the mean free path λ in a gas?
The average distance a molecule travels between collisions
What happens to the mean free path λ at constant volume when the temperature increases?
It remains the same
What is the relation between the collision frequency z and the pressure p?
z ∝ p
What is the value of the mean speed c̄rel for N₂ at 298 K and 100000 Pa?
475 m/s
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
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
What is the expression for the root mean square speed of the molecules?
c = √(3RT/M)
What is the significance of the Maxwell-Boltzmann distribution?
It describes the distribution of speeds of molecules in a gas
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
This quiz covers the rates of chemical reactions, including how to express rates as changes in concentration over time and how to calculate rate constants. It also covers the units of rate constants and how to rearrange equations to solve for rate constants.
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