AP Chemistry Flashcards: Endothermic and Exothermic Processes
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 11 cards to help you master important concepts.
In a chemical reaction, how is the system's energy affected in an exothermic vs. an endothermic process?
In an exothermic reaction, the system's energy decreases, while in an endothermic reaction, the system's energy increases.
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In a chemical reaction, how is the system's energy affected in an exothermic vs. an endothermic process?
In an exothermic reaction, the system's energy decreases, while in an endothermic reaction, the system's energy increases.
What determines if the formation of a solution is an endothermic or exothermic process?
The energy change depends on the relative strengths of the intermolecular or interparticle interactions before and after the dissolution process.
What is an endothermic process?
An endothermic process is one in which a system's energy increases by gaining energy from the surroundings.
Describe the flow of energy between a system and its surroundings during an endothermic process.
In an endothermic process, energy is gained by the system from the surroundings, causing the system's energy to increase.
What is an exothermic process?
An exothermic process is one in which a system's energy decreases as it loses energy (as heat or work) to the surroundings.
What is the primary observable indicator of energy changes in a system?
Temperature changes in a system are a primary indicator that energy changes have occurred.
Besides chemical transformations, name two other processes that can be endothermic or exothermic.
The heating or cooling of a substance and phase changes are two other processes that involve energy changes.
A student dissolves a salt in water and observes the temperature of the water dropping. Is this process endothermic or exothermic?
The process is endothermic because the system (the dissolving salt) is absorbing energy from the surroundings (the water), causing the water's temperature to decrease.
If a chemical reaction is exothermic, what happens to the temperature of the surroundings?
The temperature of the surroundings will increase because the system is losing energy in the form of heat to the surroundings.
Explain the relationship between a physical transformation and its associated energy changes.
A physical transformation, such as a phase change or dissolution, is always accompanied by an energy change, which can be observed and classified as either endothermic or exothermic.
How are experimental observations, such as a beaker feeling cold, related to energy changes?
Experimental observations provide evidence of energy changes; a beaker feeling cold indicates an endothermic process is absorbing heat from the surroundings (the beaker and your hand).