Pure substances and mixtures Original Scenario-Based Practice

Questions

1. 1.

   Deep-space exploration probe Astraea retrieves two sealed fluid samples from an uncharted cryo-comet for compositional analysis. Automated sensors observe that Sample X boils over a fluctuating temperature range between 68 °C and 84 °C and can be physically separated into two distinct liquids by simple fractional distillation. In contrast, Sample Y melts sharply at an unvarying temperature of -114 °C, retains uniform density throughout, and can only be split into simpler constituents through a high-energy chemical reaction yielding elements in an unalterable mass ratio. Based on these observed properties, which statement accurately classifies the two extraterrestrial specimens?

   • A) Both samples are pure substances because they were collected in stable fluid states from the same natural environment.
   • B) Sample X is a compound because it separates into two distinct liquids, while Sample Y is a homogeneous mixture because of its uniform density.
   • C) Both samples are heterogeneous mixtures because any matter retrieved from a comet consists of randomly combined interplanetary debris.
   • D) Sample X is a mixture because it exhibits a boiling range and is physically separable, whereas Sample Y is a pure substance because it has a sharp melting point and fixed chemical composition.

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