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WorksheetsThermochemistry
Total questions: 35
Worksheet time: 18mins
What is thermodynamics primarily concerned with?
The study of matter only
The study of energy and its transformations
The study of the universe
The study of plants and light bulbs
What does the first law of thermodynamics state about energy?
Energy can be created and destroyed.
Energy can only be transferred or changed from one form to another.
Energy remains constant and cannot be used for work.
Energy can be stored indefinitely without any loss.
What is another name for the first law of thermodynamics?
Law of Energy Dissipation
Law of Energy Conservation
Law of Energy Expansion
Law of Energy Destruction
What type of potential energy is stored in the nucleus of atoms?
Chemical
Elastic
Nuclear
Gravitational
Which type of kinetic energy is associated with the movement of atoms or molecules?
Radiant
Thermal
Mechanical
Electrical
Gravitational energy is stored based on what aspect of an object?
Chemical composition
Height
Mass
Speed
What type of energy is delivered by charged particles?
Mechanical
Nuclear
Thermal
Electrical
Which type of kinetic energy travels in waves?
Radiant
Thermal
Mechanical
Electrical
What is energy transformation?
The process of creating energy from nothing
The movement of energy from one location to another
The process of converting energy from one type to another
The destruction of energy
Which of the following is NOT an example of energy transformation?
A flashlight emitting light
A person skydiving
A person warming their hands
A battery losing charge without use
According to the concept of energy transformation, what must all types of energy use involve?
Conversion to electrical energy
Some sort of energy transfer
Use of mechanical energy
Generation of heat energy
What does the "system" refer to in a chemical context?
The entire universe except the reaction area
The specific area where chemical reactions occur and bonds are formed or broken
Any laboratory equipment used during experiments
The external environment affecting the reaction
Which of the following is considered part of the "surroundings" in a chemical experiment?
The chemical bonds being broken within the reaction
The beaker containing the reactants
The bonds forming in the reaction system
The chemical reactions themselves
When measuring temperature changes during a chemical reaction, what are we actually measuring?
The temperature of the system only
The temperature of the surroundings only
The temperature of both the system and the surroundings
The temperature of the laboratory
What is an endothermic process?
A) A process where the system loses heat energy to the surroundings.
B) A process where the system gains heat energy from the surroundings.
C) A process where the temperature of the system remains constant.
D) A process where the system converts mechanical energy into heat energy.
What happens in an exothermic process?
A) The system gains heat energy from the surroundings.
B) The system loses heat energy to the surroundings.
C) The system absorbs light energy from the surroundings.
D) The system produces electrical energy.
What does the term "Enthalpy" describe in chemical reactions?
The speed of the reaction
The energy content of a system
The pressure within the system
The temperature change of the reaction
What is the sign of ΔH when the reaction is exothermic?
Positive
Zero
Negative
Constant
During an endothermic reaction, how does the enthalpy (ΔH) change?
Decreases
Remains the same
Increases
Fluctuates
Which of the following examples is the endothermic reaction?
CH₄(g) + 2 O₂(g) → CO₂(g) + 2 H₂O(l), ΔH = -890.1 kJ/mol_rxn
N₂(g) + 2 NO(g) → 2 N₂O(g), ΔH = 73.8 kJ/mol_rxn
2 H₂(g) + O₂(g) → 2 H₂O(g), ΔH = -241.8 kJ/mol_rxn
C(s) + O₂(g) → CO₂(g), ΔH = -393.5 kJ/mol_rxn
What type of reaction is characterized by a release of energy, as indicated by a negative ΔH value?
Endothermic reaction
Exothermic reaction
Synthesis reaction
Decomposition reaction
Which of the following chemical reactions is an example of an exothermic reaction?
CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g), ΔH = -802 kJ
C₂H₅OH → 2C + 3H₂ + 0.5O₂, ΔH = 228 kJ/mol
S(s) + O₂(g) → SO₂(g), ΔH = -296.0 kJ
None of the above
In the reaction CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l), what does the ΔH value of -890.1 kJ/mol indicate about the heat change?
Heat is absorbed
Heat is released
No heat change occurs
Heat quantity is insufficient
What occurs when two systems of different temperatures come into contact?
They remain at their initial temperatures.
Energy is transferred from the cooler system to the hotter one.
Energy is transferred from the hotter system to the cooler one until their temperatures are equal.
No energy transfer occurs.
What is the term used to describe the point at which two systems reach the same temperature?
Thermal resistance
Thermal equilibrium
Heat capacity
Thermal expansion
What does the peak of the curve in an endothermic potential energy diagram represent?
The lowest energy state of the reactants
The activation energy needed for the reaction
The total energy released by the reaction
The final energy state of the products
Which diagram typically shows a higher initial energy state before the peak?
Endothermic
Exothermic
Both show the same initial energy state
Neither diagram shows energy states
What characteristic of the exothermic potential energy diagram indicates that energy is released in the reaction?
The peak is higher than the initial state
The final state is lower than the initial state
The curve is below the initial state throughout
The curve returns to the initial state
What does the peak of the curve in the reaction energy profile represent?
Reactants
Products
Activated Complex
Enthalpy
What is the term used to describe the minimum energy that must be overcome to start a chemical reaction?
Enthalpy
Transition State
Activation energy
Reaction Coordinate
Consider the following energy diagrams, which diagrams represent endothermic reactions?
Diagram A
Diagram B
Diagram C
Diagram D
What is the primary role of catalysts in a chemical reaction?
To increase the activation energy of the reaction
To be consumed completely during the reaction
To lower the activation energy of the reaction without being consumed
To act as a reactant
Refer to the diagram. What does the orange line represent in the energy diagram?
Energy path of the reaction with a catalyst
Energy path of the reaction without a catalyst
Total energy absorbed by the catalyst
Difference in energy between reactants and products
Does the graph represent an endothermic or exothermic reaction?
Endothermic
Exothermic
Both
Neither
How much energy is released during the reaction according to the diagram?
50 kJ
100 kJ
150 kJ
200 kJ
