Physical Chemistry Basics: Master the Fundamentals of Matter and Energy

Question 1

In a chemical reaction, the enthalpy change is:

Accepted Answer

The difference in enthalpy between products and reactants

Answer

Always positive

Answer

Independent of temperature

Answer

Conserved within the system

Question 2

Which of the following is NOT a characteristic of an ideal gas?

Accepted Answer

Particles interact strongly with each other.

Answer

Particles have negligible volume.

Answer

Particles move in straight lines until they collide with each other or the container.

Answer

Gas pressure is directly proportional to temperature.

Question 3

Which of the following is a colligative property, a property that depends on the concentration of solute particles in a solution?

Accepted Answer

Vapor pressure lowering

Answer

Enthalpy change

Answer

Density

Answer

Solubility

Question 4

Which of the following is NOT a fundamental state of matter?

Accepted Answer

Supercritical Fluid

Answer

Solid

Answer

Liquid

Answer

Gas

Question 5

Which property is characteristic of the solid state?

Accepted Answer

Fixed shape and well-defined volume

Answer

Fixed shape but no well-defined volume

Answer

Well-defined volume but no fixed shape

Answer

No fixed shape and no well-defined volume

Question 6

Which of the following factors **does not** influence the reaction rate of a chemical process?

Accepted Answer

Molecular weight of reactants

Answer

Temperature

Answer

Concentration of reactants

Answer

Surface area of reactants

Question 7

The equilibrium constant, K, for a chemical reaction represents the:

Accepted Answer

Relative amounts of reactants and products at equilibrium

Answer

Rate at which the forward and reverse reactions occur

Answer

Extent to which the reaction proceeds in the forward direction

Answer

Amount of energy released or absorbed during the reaction

Question 8

Enthalpy change (ΔH) of a reaction corresponds to the:

Accepted Answer

Heat transferred at constant pressure

Answer

Change in internal energy of the system

Answer

Maximum work done by the system

Answer

Change in entropy of the system

Question 9

Activation energy (Ea) of a reaction is the:

Accepted Answer

Minimum energy required for the reaction to occur

Answer

Maximum energy released during the reaction

Answer

Change in energy of the system after the reaction

Answer

Rate constant of the reaction

Question 10

The equilibrium constant (Keq) for a reaction is:

Accepted Answer

The ratio of the concentrations of products to reactants at equilibrium.

Answer

The ratio of the rate constants of the forward and reverse reactions.

Answer

The change in free energy of the reaction.

Answer

The temperature at which the reaction reaches equilibrium.

Question 11

Which of the following is a weak acid?

Accepted Answer

Acetic acid

Answer

Hydrochloric acid

Answer

Sulfuric acid

Answer

Nitric acid

Question 12

A reaction has a negative enthalpy change. This indicates that the reaction is:

Accepted Answer

Exothermic

Answer

Endothermic

Answer

Adiabatic

Answer

Isothermal

Question 13

The rate law for the reaction A + 2B → C is rate = k[A][B]^2. The order of the reaction with respect to B is:

Accepted Answer

2

Answer

0

Answer

1

Answer

3

Question 14

Which of the following processes is characterized by a decrease in both entropy and enthalpy?

Accepted Answer

Freezing

Answer

Melting

Answer

Vaporization

Answer

Deposition

Question 15

The equilibrium constant for a reaction is a measure of:

Accepted Answer

The position of the equilibrium

Answer

The rate of the reaction

Answer

The activation energy of the reaction

Answer

The temperature dependence of the reaction

Question 16

Which of the following gases is NOT an ideal gas at standard temperature and pressure?

Accepted Answer

Ammonia

Answer

Hydrogen

Answer

Helium

Answer

Nitrogen

Question 17

Which of the following is NOT a state of matter at standard conditions?

Accepted Answer

Bose-Einstein condensate

Answer

Solid

Answer

Liquid

Answer

Gas

Question 18

The first law of thermodynamics states that the total energy of an isolated system is:

Accepted Answer

Constant

Answer

Increasing

Answer

Decreasing

Answer

Unpredictable

Question 19

The rate law for a first-order reaction can be expressed as:

Accepted Answer

Rate = k[A]

Answer

Rate = k[A]^2

Answer

Rate = k[A][B]

Answer

Rate = k[A]/[B]

Question 20

Which of the following factors does NOT influence the reaction rate of a chemical reaction?

Accepted Answer

Solvent viscosity

Answer

Temperature

Answer

Concentration of reactants

Answer

Nature of the reactants

Question 21

The equilibrium constant, K_eq, for a reaction represents the:

Accepted Answer

Ratio of products to reactants at equilibrium concentrations

Answer

Ratio of forward to reverse reaction rates

Answer

Change in free energy (ΔG)

Answer

Temperature at which the reaction reaches equilibrium

Question 22

The standard enthalpy of formation of an element in its standard state is defined as:

Accepted Answer

Zero

Answer

Positive

Answer

Negative

Answer

Dependent on temperature

Question 23

Which of the following substances is a weak electrolyte?

Accepted Answer

NH3

Answer

HCl

Answer

NaOH

Answer

NaCl

Question 24

Which of the following is **not** a colligative property?

Accepted Answer

Density

Answer

Boiling point elevation

Answer

Freezing point depression

Answer

Osmotic pressure

Question 25

The ideal gas law is expressed by the equation:

Accepted Answer

PV = nRT

Answer

PV = nRT/V

Answer

PV/T = nR

Answer

nPV = RT

Question 26

The equilibrium constant for a reaction is a measure of:

Accepted Answer

The extent of the reaction

Answer

The rate of the reaction

Answer

The direction of the reaction

Answer

The activation energy of the reaction

Question 27

The study of energy transfer and transformations accompanying chemical and physical processes is known as:

Accepted Answer

Thermodynamics

Answer

Kinetics

Answer

Quantum Mechanics

Answer

Electrochemistry

Question 28

The expression that relates the rate of a reaction to the concentrations of the reactants is called the:

Accepted Answer

Rate law

Answer

Equilibrium constant

Answer

Activation energy

Answer

Reaction mechanism

Question 29

Which of the following is an example of an intensive property?

Accepted Answer

Temperature

Answer

Mass

Answer

Volume

Answer

Solubility

Question 30

Entropy is a measure of a system's:

Accepted Answer

Disorder or randomness

Answer

Energy

Answer

Temperature

Answer

Pressure

Question 31

The Gibbs free energy is a useful quantity for determining:

Accepted Answer

The spontaneity of a reaction under specific conditions

Answer

The products of a reaction

Answer

The equilibrium constant for a reaction

Answer

The rate of a reaction

Question 32

The rate law for a chemical reaction is an expression that relates:

Accepted Answer

The rate of the reaction to the concentrations of the reactants

Answer

The rate of the reaction to the temperature

Answer

The concentrations of the reactants to the temperature

Answer

The rate of the reaction to the surface area of the reactants

Question 33

The equilibrium constant for a chemical reaction is a measure of:

Accepted Answer

The extent to which the reaction proceeds

Answer

The rate at which the reaction proceeds

Answer

The spontaneity of the reaction

Answer

The enthalpy change of the reaction

Question 34

The ideal gas law is:

Accepted Answer

PV = nRT

Answer

PV/T = nR

Answer

V/T = nR

Answer

P/V = nRT

Question 35

Which of the following is a property of a spontaneous process?

Accepted Answer

The Gibbs energy of the system decreases

Answer

The entropy of the system decreases

Answer

The enthalpy of the system increases

Answer

The free energy of the system increases

Question 36

Which of the following is a transition state?

Accepted Answer

An unstable intermediate formed during a chemical reaction

Answer

A stable intermediate formed during a chemical reaction

Answer

The lowest energy state of a molecule

Answer

The highest energy state of a molecule