A jeweler sends five samples to a laboratory for compositional analysis
CHEMISTRY · Multi-part · AP · Chemistry · Atomic Structure and Properties · Atomic Structure and Properties
Problem
A jeweler sends five samples to a laboratory for compositional analysis. Macroscopic descriptions of the samples are provided in the table.
Sample 1 A clear, colorless liquid labeled "distilled water"
Sample 2 A yellow metal alloy stamped "14 K"
Sample 3 A white, crystalline solid that sublimes at −78 °C, leaving no residue
Sample 4 A colorless gas collected above seawater at 20 °C and 1 atm
Sample 5 A silvery metal that melts when held in the hand (melting point 29.8 °C)
Use the information above to answer the following questions.
(a) For EACH sample (1–5), state whether it is best classified as a pure substance or a mixture.
(b) For EACH classification in part (a), provide a chemical justification that references the definition of a pure substance or a mixture and any relevant macroscopic observations (e.g., melting point, composition, phase behavior).