CHEMISTRY · Multi-part · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
Three sealed vials—A, B, and C—each contain the same volume of liquid water at room temperature. Two solutes are present in every vial:
• MgCl₂, which dissociates completely
• Ethanol (C₂H₅OH), which remains as intact molecules
A careful particulate count for a standard analysis box placed inside each vial gives the following results:
• Vial A: 4 Mg²⁺ ions, 8 Cl⁻ ions, 6 ethanol molecules
• Vial B: 3 Mg²⁺ ions, 6 Cl⁻ ions, 12 ethanol molecules
• Vial C: 5 Mg²⁺ ions, 10 Cl⁻ ions, 4 ethanol molecules
Answer the questions that follow.
(a) Rank the three vials in order of decreasing concentration of MgCl₂ (highest to lowest). Clearly indicate ties, if any, and justify your ranking using the particle counts.
(b) Rank the vials in order of decreasing concentration of ethanol (highest to lowest). Justify your answer.
(c) Identify which vial is expected to exhibit the greatest electrical conductivity. Support your choice with specific reference to the particulate information provided.