Chemistry Chapter 4: Reaction Rates and Equilibrium

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Questions and Answers

What does the term 'activation energy' refer to in a chemical reaction?

Energy barrier that must be overcome for a reaction to occur (correct)

Energy required to break bonds

Energy required to form products

Energy released during exothermic reactions

For a pseudo first-order reaction, what is implied about the concentration of one reactant?

It changes significantly throughout the reaction

It is not involved in the rate law

It remains constant during the reaction (correct)

It must be zero for the reaction to occur

In a zero-order reaction, how is the rate of reaction dependent on the concentration of reactants?

It is directly proportional to concentration

It is independent of concentration (correct)

It decreases exponentially with concentration

It doubles with each increment in concentration

When is the rate law of a reaction derived?

From experimental data related to reaction rates and concentrations (A) Signup and view all the answers

What does the rate constant (k) indicate in a reaction's rate law?

The speed of the reaction at a given temperature (D) Signup and view all the answers

What does the variable 'k' represent in the equation for the rate of the reaction?

The rate constant of the reaction (D) Signup and view all the answers

Under what condition can a reaction behave as a first-order reaction despite not truly being one?

When one reactant is in excess (C) Signup and view all the answers

What is the half-life of a reactant?

The time in which the concentration of a reactant is reduced to one half of its initial concentration (D) Signup and view all the answers

In the equation for the rate of reaction, which concentrations are multiplied together?

[A] and [B], and also their respective orders (D) Signup and view all the answers

Which of the following reactions is mentioned as behaving in a certain manner under specified conditions?

Acid hydrolysis of ethyl acetate (C) Signup and view all the answers

What does molarity measure?

Moles of solute per liter of solution (B) Signup and view all the answers

Which of the following describes normality?

Number of gram equivalents of solute per liter of solution (D) Signup and view all the answers

How is mole fraction calculated?

Number of moles of solute divided by the total number of moles of all components (D) Signup and view all the answers

Which unit is commonly used for expressing mass by volume percentage (w/v)?

Grams per milliliter (B) Signup and view all the answers

What does parts per million (ppm) typically represent?

Trace quantities of solute (B) Signup and view all the answers

What is the formula used to calculate mass percentage (w/w)?

Mass of solute divided by total mass of solution (D) Signup and view all the answers

Which of the following statements is true about normality?

Normality depends on the chemical reaction for which the solution is used (A) Signup and view all the answers

What is the primary purpose of using mind maps?

To visually connect and organize concepts (A) Signup and view all the answers

In mind mapping, which level of association is represented by the thickest line?

First Level of Association (A) Signup and view all the answers

How do associations in mind maps contribute to memory strength?

By connecting unrelated concepts (B) Signup and view all the answers

Which of the following crystal systems has the parameters a = b = c and angles $\alpha = \beta = \gamma = 90°$?

Cubic (B) Signup and view all the answers

What defines the Tetragonal crystal system?

a = b ≠ c (A) Signup and view all the answers

Which crystal system is characterized by having angles $\alpha = \beta = 90°$ and $\gamma > 90°$?

Monoclinic (C) Signup and view all the answers

Which of the following is not a type of crystal system mentioned?

Spherical (B) Signup and view all the answers

What is the characteristic of the Rhombohedral crystal system?

All sides are equal, but angles are not 90 degrees (B) Signup and view all the answers

What differentiates the Hexagonal system in terms of axes?

Two axes are equal and one is different (A) Signup and view all the answers

Which intermolecular force is relevant for materials held by dipole-dipole interactions?

Hydrogen bonds (B) Signup and view all the answers

Which crystal system is described as having a base-centered structure?

Body-centered (C) Signup and view all the answers

What kind of forces hold atoms or molecules in gases?

Weak London dispersion forces (D) Signup and view all the answers

How are molecules held in a covalent bond?

By shared electrons (C) Signup and view all the answers

What characterizes a cubic crystal structure compared to others?

All sides and angles are equal (A) Signup and view all the answers

What is the relationship between temperature and osmotic pressure?

Osmotic pressure increases with decrease in temperature (D) Signup and view all the answers

What is the formula for calculating osmotic pressure?

Π = CRT (D) Signup and view all the answers

How does the normal molar mass compare to abnormal molar mass?

Normal molar mass is generally less than abnormal molar mass (A) Signup and view all the answers

What is the depression in freezing point formula?

ΔTf = M2 × W1 (B) Signup and view all the answers

What is the expected sign for the enthalpy change when solution formation is endothermic?

ΔH mix > 0 (C) Signup and view all the answers

When solubility increases, what type of enthalpy change is indicated?

Endothermic where ΔH > 0 (C) Signup and view all the answers

What does Raoult’s Law state regarding partial vapor pressure?

Partial vapor pressure is directly proportional to mole fraction (C) Signup and view all the answers

What characterizes a minimum boiling azeotrope?

Positive ΔH mix (C) Signup and view all the answers

What signifies an ideal solution?

ΔH mix is negative (B) Signup and view all the answers

Which type of solution likely results in a maximum boiling azeotrope?

Mixture of chloroform and acetone (B) Signup and view all the answers

Which of the following defines colligative properties?

Properties that depend only on the number of solute particles (D) Signup and view all the answers

In the context of colligative properties, which factor does not affect the vapor pressure of a solution?

Chemical nature of solute (C) Signup and view all the answers

What is the effect of pressure increase on boiling point?

Boiling point increases (D) Signup and view all the answers

Which of the following represents a gas-liquid solution?

O2 dissolved in water (C) Signup and view all the answers

What is the unit of the rate constant for a first order reaction?

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

How is the half-life (t1/2) equation for a zero order reaction expressed?

t1/2 = [R]0 / k (A) Signup and view all the answers

What is the relationship of concentration to time in a first order reaction?

Concentration decreases exponentially over time. (D) Signup and view all the answers

Which statement is true concerning the reaction order?

The rate of a zero order reaction is constant regardless of concentration. (C) Signup and view all the answers

What is the correct relationship for half-life (t1/2) of a first order reaction?

t1/2 = 0.693 / k (C) Signup and view all the answers

Which order of reaction would you expect to have a constant rate regardless of the concentration of reactants?

Zero order (B) Signup and view all the answers

Which of the following expressions represents the rate of a zero order reaction?

Rate = k (C) Signup and view all the answers

For which type of reaction would doubling the initial concentration lead to double the rate of reaction?

Second order reaction (B) Signup and view all the answers

How does the rate constant (k) affect the half-life of a zero order reaction?

As k increases, half-life decreases. (B) Signup and view all the answers

Which expression accurately describes half-life for a zero order reaction?