Mar 13 learn.flvs.net Lessons Assessments Gradebook Email 7 Tools My Courses Question 2(Multiple Choice Worth 2 points) (05.04 MC) A scientist discovers a new substance. The molecules of the substance form hydrogen bonds with each other. When the molecules lose a lot of energy, the hydrogen bonds hold them relatively far apart. Based on this information, what can the scientist infer about the substance? It expands when it freezes. It is highly colored. It exists only as a gas. It does not dissolve ionic compounds. Question 3(Multiple Choice Worth 2 points) (05.04 MC) Which of these best explains what happens when the ionic substance calcium chloride \( \left(\mathrm{CaCl}_{2}\right) \) dissolves in water?

**Question 2** 1. The substance has molecules that form hydrogen bonds. 2. When the molecules lose a lot of energy (i.e., as the substance cools), the hydrogen bonds hold the molecules farther apart. 3. This behavior is similar to that of water, where the solid form (ice) has an open, hexagonal structure that occupies more space than the liquid form. 4. Thus, the substance expands when it freezes. \[ \textbf{Answer: It expands when it freezes.} \] **Question 3** 1. Calcium chloride has the formula \( \mathrm{CaCl}_2 \), which is an ionic compound. 2. In water, which is a polar solvent, the positive and negative ends of water molecules interact with the ions. 3. The slightly negative oxygen atoms in water attract the positive \( \mathrm{Ca}^{2+} \) ions, and the slightly positive hydrogen atoms attract the negative \( \mathrm{Cl}^{-} \) ions. 4. These interactions overcome the ionic attractions between \( \mathrm{Ca}^{2+} \) and \( \mathrm{Cl}^{-} \) in the solid state, effectively separating them and allowing the compound to dissolve. \[ \textbf{Answer: Water molecules surround the ions, pulling them apart and allowing \( \mathrm{CaCl}_2 \) to dissociate in solution.} \]