#1
Which law of thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another?
Zeroth law
First law
Second law
Third law
#2
What is the SI unit of energy?
#3
Which term refers to the energy required to raise the temperature of one gram of a substance by one degree Celsius?
Enthalpy
Entropy
Specific heat
Gibbs free energy
#4
In an exothermic reaction, what happens to the enthalpy change (ΔH)?
It increases
It decreases
It remains constant
It depends on the reaction
#5
Which term describes the total energy content of a system?
Enthalpy
Entropy
Internal energy
Gibbs free energy
#6
What is the standard state for enthalpy of formation?
1 atm pressure and 0°C temperature
1 atm pressure and 25°C temperature
1 atm pressure and 100°C temperature
10 atm pressure and 0°C temperature
#7
Which of the following statements is true regarding an endothermic reaction?
It releases heat to the surroundings
It absorbs heat from the surroundings
It neither absorbs nor releases heat
It depends on the specific reaction conditions
#8
What does a negative value of Gibbs free energy (∆G) indicate for a reaction?
The reaction is at equilibrium
The reaction is non-spontaneous
The reaction is spontaneous
The reaction is reversible
#9
What is the definition of enthalpy?
The energy required to create a system
The heat content of a system at constant pressure
The randomness or disorder of a system
The amount of energy available to do work
#10
What does Hess's Law state?
The total energy of an isolated system is constant
The heat absorbed or released in a chemical process is the same whether the process occurs in one or several steps
The entropy of the universe is always increasing
Energy can neither be created nor destroyed in a chemical reaction
#11
What is the symbol for standard enthalpy change?
#12
Which of the following statements best defines the term 'adiabatic'?
A process in which no heat is transferred between the system and its surroundings
A process that occurs at constant pressure
A process in which the volume of the system remains constant
A process that occurs at constant temperature
#13
What is the significance of the heat capacity of a substance?
It measures the amount of heat required to raise the temperature of a substance by 1°C
It measures the amount of heat released or absorbed by a substance during a chemical reaction
It measures the energy required to break the bonds within a substance
It measures the ability of a substance to conduct electricity
#14
In which type of reaction does the enthalpy increase?
Exothermic reaction
Endothermic reaction
Neutralization reaction
Combustion reaction
#15
Which of the following statements about Hess's Law is true?
It states that the enthalpy change of a reaction depends only on the initial and final states of the reactants
It allows the calculation of the overall enthalpy change for a reaction by summing the enthalpy changes for each step of the reaction
It describes the relationship between temperature and the equilibrium constant of a reaction
It is only applicable to ideal gases
#16
Which law of thermodynamics defines absolute zero as the point where entropy is at a minimum?
Zeroth law
First law
Second law
Third law
#17
What is the relationship between the standard enthalpy change (∆H°) and the standard internal energy change (∆U°) for a reaction at constant pressure?
∆H° = ∆U°
∆H° = ∆U° + PV
∆H° = ∆U° + P∆V
∆H° = ∆U° + nRT
#18
Which quantity represents the maximum amount of useful work that can be obtained from a system at constant temperature and pressure?
Enthalpy
Entropy
Gibbs free energy
Internal energy
#19
Which of the following is NOT a state function?
Enthalpy
Entropy
Work
Internal energy
#20
What is the relationship between the standard enthalpy of reaction (∆H°) and the heat of reaction (∆H) at non-standard conditions?
∆H° = ∆H + ∆nRT
∆H° = ∆H + P∆V
∆H° = ∆H + RTln(Q)
∆H° = ∆H + nRTln(Q)
#21
Which law of thermodynamics states that the entropy of a perfect crystal at absolute zero is zero?
Zeroth law
First law
Second law
Third law
#22
Which of the following factors affect the value of the heat of formation of a compound?
The phase of the compound
The temperature at which it is formed
The pressure at which it is formed
All of the above
#23
What is the standard heat of reaction?
The heat released when one mole of a substance burns in oxygen
The heat change for a reaction when it occurs in the molar quantities expressed in a chemical equation under standard conditions
The heat change for a reaction when it occurs in a calorimeter
The heat required to raise the temperature of a substance by 1 degree Celsius
#24
Which of the following statements about standard enthalpy of formation (∆H°f) is correct?
It is the heat change when one mole of a substance is formed from its elements in their standard states
It is the heat change when one mole of a substance reacts with oxygen
It is the heat change when one mole of a substance dissolves in water
It is the heat change when one mole of a substance changes phase
#25
What is the relationship between enthalpy (∆H) and internal energy (∆U) in a system?
∆H = ∆U + PV
∆H = ∆U + P∆V
∆H = ∆U - P∆V
∆H = ∆U - PV