CHEMISTRY · Multi-part · AP · Chemistry · Compound Structure and Properties · Compound Structure and Properties
Problem
Three pure substances—labeled A, B, and C—have the following chemical formulas:
Substance A: Na2SO4
Substance B: CO2
Substance C: SiO2
Assume each sample is macroscopic and consists only of the compound listed. Use the information provided as well as periodic trends in bonding to analyze and classify the type of pure substance represented by each formula.
(1) Classify substance A as molecular, ionic, or network covalent. Provide a clear justification that references the elements present and the arrangement of ions or atoms in the solid.
(2) Classify substance B as molecular, ionic, or network covalent. Provide a clear justification that references bonding and intermolecular forces.
(3) Classify substance C as molecular, ionic, or network covalent. Provide a clear justification that references atomic structure and bonding.
(4) Rank the expected melting points of A, B, and C from lowest to highest. Support your ranking by connecting the type of bonding and structure you identified in parts (a)–(c) to thermal properties.