At the end of which phase change will a substance have less energy than it did at the beginning?

Question

At the end of which phase change will a substance have less energy than it did at the beginning??  
A. Deposition  
B. Melting  
C. Sublimation  
D. Vaporization

Accepted Answer

Correct Answer: (A)Deposition. 
Rationale: At the end of deposition, a substance will have less energy than it did at the beginning.Phase changes involve the absorption or release of thermal energy (heat). The internal energy of a substance is related to the kinetic and potential energy of its particles. Changes to a more ordered state (e.g., gas to solid) release energy, lowering the substance's internal energy.A) DepositionDeposition is the phase change where a gas turns directly into a solid, bypassing the liquid phase (e.g., frost forming from water vapor). This is an exothermic process that releases a significant amount of latent heat into the surroundings. The gas particles, which have high kinetic energy and are widely dispersed, lose energy and become locked into the fixed, ordered lattice of a solid. The decrease in particle motion and potential energy results in a substantial net loss of internal energy for the substance.B) MeltingMelting is the change from solid to liquid. This process is endothermic, requiring an input of heat energy to overcome the intermolecular forces holding the solid lattice together. The added energy increases the particles' kinetic energy, allowing them to slide past one another. Therefore, the substance has more internal energy as a liquid than it did as a solid.C) SublimationSublimation is the direct change from solid to gas (e.g., dry ice becoming CO₂ gas). This is a highly endothermic process. It requires energy to break the strong intermolecular bonds of the solid and additionally to allow the particles to disperse as a gas. The resulting gas particles possess high kinetic energy and greater separation, meaning the substance's internal energy increases dramatically.D) VaporizationVaporization (evaporation or boiling) is the change from liquid to gas. This process requires a large input of heat energy, known as the enthalpy of vaporization, to break the attractive forces between liquid molecules and allow them to separate into the gaseous state. The gaseous state has much higher particle kinetic energy and greater intermolecular distances, leading to a significant increase in the substance's internal energy.Conclusion:Phase changes that result in a more ordered, condensed state (gas to liquid, liquid to solid, gas to solid) are exothermic and decrease the internal energy of the substance. Deposition, the transition from gas directly to solid, results in the greatest increase in order and therefore the largest release of energy, leaving the substance with less energy than it started with.

At the end of which phase change will a substance have less energy than it did at the beginning?

A
Deposition

B
Melting

C
Sublimation

D
Vaporization

At the end of deposition, a substance will have less energy than it did at the beginning.

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At the end of which phase change will a substance have less energy than it did at the beginning?

A Deposition B Melting C Sublimation D Vaporization

At the end of deposition, a substance will have less energy than it did at the beginning.

Topic Flashcards

Mini Quiz

Related Questions

A
Deposition

B
Melting

C
Sublimation

D
Vaporization