Podcast
Questions and Answers
Potential Energy is energy stored in the ______ bonds of a substance.
Potential Energy is energy stored in the ______ bonds of a substance.
chemical
An endothermic reaction is a reaction where the system absorbs energy from the surrounding in the form of ______.
An endothermic reaction is a reaction where the system absorbs energy from the surrounding in the form of ______.
heat
Examples of an endothermic reaction include evaporation of ______.
Examples of an endothermic reaction include evaporation of ______.
liquid
Exothermic reaction is a reaction that releases energy from the system in the form of ______.
Exothermic reaction is a reaction that releases energy from the system in the form of ______.
Signup and view all the answers
Examples of an exothermic reaction include burning of a ______.
Examples of an exothermic reaction include burning of a ______.
Signup and view all the answers
Kinetic Energy is energy that comes from ______.
Kinetic Energy is energy that comes from ______.
Signup and view all the answers
The first law of thermodynamics states that energy can neither be created nor destroyed but can only changed from one form to another. Heat (q) and work (w) are the only possible forms of energy transfer, this can attribute to the overall change in energy (E) of a system. So, we can write, - The change in energy is always defined as the difference between the final state and the initial state. It is a physical property of a material that measures how much heat is required to raise the temperature of one mole of that material to 1degC.
The first law of thermodynamics states that energy can neither be created nor destroyed but can only changed from one form to another. Heat (q) and work (w) are the only possible forms of energy transfer, this can attribute to the overall change in energy (E) of a system. So, we can write, - The change in energy is always defined as the difference between the final state and the initial state. It is a physical property of a material that measures how much heat is required to raise the temperature of one mole of that material to 1degC.
Signup and view all the answers
Energy is transferred into a system. Work is done on a system.
Energy is transferred into a system. Work is done on a system.
Signup and view all the answers
A process of measuring the amount of heat released or absorbed during a chemical reaction. It can determine whether the reaction is exothermic or endothermic.
A process of measuring the amount of heat released or absorbed during a chemical reaction. It can determine whether the reaction is exothermic or endothermic.
Signup and view all the answers
______ is a measure of the total energy in a system/reaction. It is the total heat absorbed or released in the system. Sometimes referred to as “heat content.” The heat flow of the reaction system is equal to the difference in enthalpy between products and reactant.
______ is a measure of the total energy in a system/reaction. It is the total heat absorbed or released in the system. Sometimes referred to as “heat content.” The heat flow of the reaction system is equal to the difference in enthalpy between products and reactant.
Signup and view all the answers
A chemical equation that shows enthalpy relation between products and reactants. It must contain a balanced chemical equation, and the appropriate value and for change in enthalpy.
A chemical equation that shows enthalpy relation between products and reactants. It must contain a balanced chemical equation, and the appropriate value and for change in enthalpy.
Signup and view all the answers
The sign of change in enthalpy indicates whether the reaction, when carried out at constant pressure, is endothermic (positive change in enthalpy) or exothermic (negative change in enthalpy).
The sign of change in enthalpy indicates whether the reaction, when carried out at constant pressure, is endothermic (positive change in enthalpy) or exothermic (negative change in enthalpy).
Signup and view all the answers
The magnitude of change in enthalpy is directly proportional to the amount of reactant or product.
The magnitude of change in enthalpy is directly proportional to the amount of reactant or product.
Signup and view all the answers
Change in enthalpy for a reaction is equal in magnitude but opposite in sign to change in enthalpy for the reverse reaction.
Change in enthalpy for a reaction is equal in magnitude but opposite in sign to change in enthalpy for the reverse reaction.
Signup and view all the answers
The value quoted for change in enthalpy applies when the products and reactants are at the same temperature, ordinarily taken to ______ unless specified otherwise.
The value quoted for change in enthalpy applies when the products and reactants are at the same temperature, ordinarily taken to ______ unless specified otherwise.
Signup and view all the answers
Change in enthalpy is the same whether it occurs in one step or in a series of steps.
Change in enthalpy is the same whether it occurs in one step or in a series of steps.
Signup and view all the answers
Study Notes
Potential and Kinetic Energy
- Potential Energy is stored in the chemical bonds of a substance.
- Kinetic Energy arises from the motion of particles within a system.
Endothermic and Exothermic Reactions
- Endothermic reactions absorb energy from the surroundings in the form of heat.
- An example of an endothermic reaction includes the evaporation of water.
- Exothermic reactions release energy, typically as heat.
- An example of an exothermic reaction is the burning of a fuel.
Thermodynamics Principles
- The first law of thermodynamics asserts that energy cannot be created or destroyed, only transformed.
- Heat (q) and work (w) are the only forms of energy transfer affecting a system's energy change (ΔE).
- The change in energy is defined as the difference between the final state and the initial state of the system.
Measuring Heat and Enthalpy
- Specific heat capacity measures heat required to raise the temperature of one mole of a material by 1°C.
- Energy can be transferred into a system as work is done on it.
- Calorimetry is used to measure the amount of heat released or absorbed during a chemical reaction, determining if it is endothermic or exothermic.
- Enthalpy (H) is the total energy in a system or reaction, also known as "heat content."
Enthalpy Changes
- The heat flow of a reaction is equal to the difference in enthalpy between products and reactants.
- A balanced chemical equation is necessary to describe the enthalpy relationship effectively, including the change in enthalpy (ΔH).
- The sign of ΔH indicates the nature of the reaction: positive for endothermic and negative for exothermic.
- The magnitude of ΔH is proportional to the quantity of reactants or products involved.
- ΔH is equal in magnitude but opposite in sign for the reverse reaction.
- Standard conditions for quoting ΔH are at the same temperature, usually 25°C unless stated otherwise.
- The change in enthalpy remains consistent regardless of whether a reaction occurs in one step or multiple steps.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of thermodynamics and energy in chemistry with this review quiz for engineering students. Topics include potential energy, endothermic reactions, and more.
