Sublimation, melting, and vaporization are phase changes that are ______________________.
exothermic
distillation
endothermic
mixture
compound
endothermic
Sublimation, melting, and vaporization are phase changes that are endothermic.
To determine which of the given options describes the phase changes of sublimation, melting, and vaporization, we need to understand the meaning of each term.
- Sublimation: This is the process in which a substance goes directly from a solid to a gas, bypassing the liquid phase.
- Melting: This is the process in which a solid substance changes into a liquid state.
- Vaporization: This is the process in which a liquid substance changes into a gaseous state.
Now, let's analyze the options:
- Exothermic: This refers to a process that releases heat or energy to the surroundings. It does not specifically describe phase changes.
- Distillation: This is a separation technique used to separate liquid mixtures based on their boiling points. It does not describe phase changes individually.
- Endothermic: This refers to a process that absorbs heat or energy from the surroundings. It does not specifically describe phase changes.
- Mixture: This refers to a combination of two or more substances that are physically mixed together but do not chemically combine. It does not describe phase changes individually.
- Compound: This refers to a substance made up of two or more different elements chemically bonded together. It does not describe phase changes individually.
Given the definitions, the correct answer is "endothermic" because both sublimation and vaporization are endothermic phase changes that require the absorption of heat or energy to occur. Melting, on the other hand, is an exception as it is exothermic, but since the question asks for phase changes as a whole, "endothermic" is the most appropriate answer.