7. Would you expect water, H 2 O , to have a higher or lower boiling point than chloromethane, CH 3 Cl ? Explain. 8. Identify the intermolecular force shown in each image ( \( \mathrm{A}, \mathrm{B} \), and C ).

### Question 7: **Would you expect water, H₂O, to have a higher or lower boiling point than chloromethane, CH₃Cl? Explain.** **Answer:** Water (H₂O) has a **higher boiling point** than chloromethane (CH₃Cl). This difference in boiling points is primarily due to the types and strengths of intermolecular forces present in each molecule. - **Water (H₂O):** - **Hydrogen Bonding:** Water molecules can form strong hydrogen bonds because each water molecule has two hydrogen atoms bonded to a highly electronegative oxygen atom. These hydrogen bonds create a tightly held network of molecules. - **Polar Molecules:** The bent shape of water leads to a polar molecule with significant dipole-dipole interactions in addition to hydrogen bonding. - **Chloromethane (CH₃Cl):** - **Dipole-Dipole Interactions:** Chloromethane is a polar molecule due to the difference in electronegativity between carbon and chlorine. However, its dipole-dipole interactions are weaker compared to hydrogen bonding. - **London Dispersion Forces:** These are present in all molecules but are the only intermolecular forces in nonpolar regions or less polar molecules like CH₃Cl. **Conclusion:** The strong hydrogen bonding in water requires more energy (higher temperature) to break compared to the weaker dipole-dipole and London dispersion forces in chloromethane. Therefore, water has a higher boiling point than chloromethane. --- ### Question 8: **Identify the intermolecular force shown in each image (A, B, and C).** **Answer:** Without the actual images, I'll outline the common types of intermolecular forces and typical representations for each. You can match these descriptions to your images labeled A, B, and C. 1. **London Dispersion Forces (Van der Waals Forces):** - **Description:** These are the weakest intermolecular forces caused by temporary dipoles induced in molecules. They are present in all molecules, whether polar or nonpolar. - **Typical Representation:** Often depicted as temporary, fluctuating attractions between nonpolar molecules or within large, nonpolar surfaces. 2. **Dipole-Dipole Interactions:** - **Description:** Occur between polar molecules where the positive end of one molecule is attracted to the negative end of another. - **Typical Representation:** Arrows showing the attraction between the partial positive (δ⁺) end of one molecule and the partial negative (δ⁻) end of another molecule. 3. **Hydrogen Bonding:** - **Description:** A special, stronger type of dipole-dipole interaction that occurs when hydrogen is bonded to highly electronegative atoms like nitrogen (N), oxygen (O), or fluorine (F). - **Typical Representation:** Lines or arrows indicating strong attractions between the hydrogen atom of one molecule and the electronegative atom of another (e.g., H—O···H—O). 4. **Ion-Dipole Forces:** - **Description:** Occur between ionic compounds and polar molecules, important in solutions like salt in water. - **Typical Representation:** Attraction between a charged ion and the partial charges on a polar molecule. **Possible Assignments for Images A, B, and C:** - **Image A:** If it shows a nonpolar molecule with temporary attractions, it's likely **London Dispersion Forces**. - **Image B:** If it shows polar molecules with partial positive and negative ends attracting each other, it's likely **Dipole-Dipole Interactions**. - **Image C:** If it depicts hydrogen atoms bonded to N, O, or F interacting strongly with another molecule's electronegative atom, it's likely **Hydrogen Bonding**. **Example Assignment:** - **A:** London Dispersion Forces - **B:** Dipole-Dipole Interactions - **C:** Hydrogen Bonding **Note:** Please refer to your specific images and match them with the descriptions above to accurately identify the intermolecular forces.