Zero and first order kinetics half-lives Arrhenius equation and activation energy - One Line Questions
1.
For a zero-order reaction, the rate of disappearance of reactant A is: —
-d[A]/dt = k
2.
If the initial concentration of a first-order reaction is [A]₀, what is the concentration after n half-lives? —
[A]₀ / (2^n)
3.
The integrated rate law for a first-order reaction A → Products is given by: —
[A]t = [A]₀ * e^(-kt)
4.
The integrated rate law for a zero-order reaction A → Products is: —
[A]t = [A]₀ - kt
5.
The integrated rate law for a first-order reaction can also be written as: —
log([A]t/[A]₀) = -kt/2.303
6.
For a zero-order reaction, if the initial concentration of reactant A is 0.5 M and the rate constant is 0.02 M/s, what is the concentration of A after 10 seconds? —
0.3 M
7.
What is the value of ln(2)? —
0.693
8.
The half-life of a first-order reaction is 10 minutes. What is the rate constant (k) in min⁻¹? —
0.0693
9.
The half-life of a zero-order reaction is 30 minutes when the initial concentration is 0.6 M. What would be the half-life if the initial concentration were 0.3 M? —
15 minutes
10.
The half-life of a first-order reaction is 20 minutes. How much time will it take for the concentration to reduce to 1/8th of its initial value? —
60 minutes
11.
For a first-order reaction, if the rate constant is 2 x 10⁻³ s⁻¹, what is its half-life in seconds? —
346.5
12.
For a first-order reaction, the concentration of the reactant decreases from 0.8 M to 0.2 M in 10 minutes. What is the half-life of this reaction? —
10 minutes
13.
For a first-order reaction, if the initial concentration is 1.0 M and after 100 seconds it becomes 0.5 M, what is the half-life of this reaction? —
100 seconds
14.
If a reaction has a half-life of 50 years, it is most likely: —
A first-order reaction
15.
In the Arrhenius equation, k = A exp(-Ea/RT), what does 'A' represent? —
Frequency factor or pre-exponential factor
16.
In the Arrhenius equation, the term exp(-Ea/RT) represents the fraction of molecules that have: —
Energy equal to or greater than the activation energy
17.
A reaction is found to have a rate constant that is independent of the initial concentration of the reactants. What is the order of this reaction? —
Zero-order
18.
What is the effect of a catalyst on the activation energy of a reaction? —
Decreases activation energy
19.
According to the Arrhenius equation, at absolute zero temperature (T=0 K), the rate constant (k) approaches: —
Zero
20.
If the temperature of a reaction is increased by 10°C, how does the rate constant typically change, according to empirical observations related to the Arrhenius equation? —
It doubles
21.
Which statement about activation energy is incorrect? —
It is independent of temperature.
22.
What is the unit of activation energy (Ea) in the Arrhenius equation? —
J/mol
23.
The slope of the plot of ln[A]t vs time for a first-order reaction is: —
-k
24.
According to the Arrhenius equation, what happens to the rate constant (k) when the temperature (T) increases? —
k increases
25.
What happens to the rate constant 'k' of a reaction as the activation energy (Ea) increases, assuming temperature remains constant? —
k decreases
26.
What is the minimum energy required for reactant molecules to undergo a chemical reaction? —
Activation energy
27.
The Arrhenius equation can be linearized by taking the logarithm of both sides. The equation becomes: —
ln k = ln A - (Ea/RT)
28.
The unit of the rate constant for a first-order reaction is: —
s⁻¹
29.
For a second-order reaction where Rate = k[A]², if the initial concentration of A is doubled, how will the rate change? —
Rate increases by a factor of 4
30.
What is the unit of the rate constant for a zero-order reaction? —
mol L⁻¹ s⁻¹
31.
The unit of the rate constant for a second-order reaction is: —
mol⁻¹ L s⁻¹
32.
For a zero-order reaction, the plot of concentration of reactant versus time is a: —
Straight line with negative slope
33.
What is the half-life of a zero-order reaction with an initial concentration [A]₀ and rate constant k? —
t½ = [A]₀ / (2k)
34.
For a first-order reaction, what is the relationship between the half-life (t½) and the initial concentration ([A]₀)? —
t½ is independent of [A]₀
35.
For a zero-order reaction, what is the relationship between the half-life (t½) and the initial concentration ([A]₀)? —
t½ is directly proportional to [A]₀
36.
The Arrhenius equation relates the rate constant (k) of a reaction to: —
Temperature and activation energy
37.
The term 'frequency factor' (A) in the Arrhenius equation represents: —
The number of collisions per unit volume per unit time
38.
The rate of a zero-order reaction is given by Rate = k. This means: —
The rate is constant regardless of reactant concentration.
39.
For a first-order reaction, the half-life is constant and does not depend on the initial concentration. This is because: —
The rate is proportional to the concentration.
40.
Which of the following statements is true for a zero-order reaction? —
The rate of reaction is constant and independent of reactant concentration.
41.
What is the definition of activation energy? —
The minimum energy required to initiate a chemical reaction
42.
The Arrhenius equation is given by k = A e^(-Ea/RT). If Ea = 0, then k will be equal to: —
A
43.
A reaction has a rate constant k = 5 x 10⁻⁴ M s⁻¹. What is the order of this reaction? —
Zero-order
44.
If the half-life of a reaction is halved when the initial concentration is doubled, the reaction is: —
Second-order
45.
If a reaction has a rate constant of 0.05 M⁻¹s⁻¹, what is the order of the reaction? —
Second-order
46.
Which order of reaction has a half-life that is directly proportional to the initial concentration? —
Zero-order
47.
If the rate of a reaction is 1.5 x 10⁻³ M/s when the concentration of the reactant is 0.3 M, and the rate becomes 6.0 x 10⁻³ M/s when the concentration is 0.6 M, what is the order of the reaction? —
First-order
48.
A reaction proceeds with a constant rate of 0.1 M/s. What is the order of this reaction? —
Zero-order
49.
If the rate constant of a reaction doubles for every 10°C rise in temperature, this is a general rule of thumb related to: —
Arrhenius equation behavior