Solids, Liquids, & Intermolecular Forces PRACTICE 1. In the chart below, give a brief word description AND draw each intermolecular force (IMF). IMF Description Drawing Dispersion / London Force temporary shift in electron density of e- in electron clouds dispersion force Dipole-Dipole Force attraction between oppositely charged ends of polar molecules dipoledipole force Hydrogen Bond dipole-dipole attraction between molecules with H(+) and F, O, or N (-) hydrogen bond 2. What types of forces would exist in samples of the following substances? Consider the Lewis Structure, polarity, and bond type. Circle all that apply. Substance Dispersion/London Dipole-Dipole Hydrogen Bonding Ionic Bond a. CF₄ ✓ b. CaBr₂ ✓ ✓ c. H₂O ✓ ✓ ✓ d. N₂ ✓ e. Ne ✓ f. BH₃ ✓ g. KBr ✓ ✓ h. CH₃OH ✓ ✓ ✓ i. CH₃CH₂CH₃ ✓ j. CH₃OCH₃ ✓ ✓ 3. Which substance would have stronger intermolecular forces? CIRCLE ONE and give your reasoning below. A polar molecule OR a non-polar molecule Answer: Polar molecule 4. Consider the following sets of substances. CIRCLE the substance with the greater IMF: a. He vs Ne vs Ar b. I2 vs Cl2 vs F2 c. Ne vs N2 d. CH4 vs SiH4 e. NH3 vs NF3 f. NH3 vs PH3 g. CH3Cl vs CH3Br h. CH3-CH2-CH2-CH2-CH2-CH3 vs CH3-CH2-CH3 5. The image below contrasts the three states of matter. Identify which diagram corresponds to a solid, liquid, and gas phase. Identify at least 2 properties of each which led you to each conclusion. State of Matter: Solid, Liquid, Gas Traits: Solid: Dense structure, rigid, fixed volume, definite shape Liquid: Less dense, fluid, takes the shape of the container, definite volume Gas: Least dense, particles don't interact, fills the entire volume of the container, no definite shape 6. Consider the following statements regarding samples of matter. Indicate whether each statement applies to a solid, liquid, or gas. For each statement, choose all that apply. a. Intermolecular forces are non-existent: G (Gas) b. Particles with a high melting point: S (Solid) c. Particles are highly organized and held together in a relatively rigid structure: S (Solid) d. Particles within the sample are moving in a random fashion: G (Gas) e. Considered a condensed state since particles in the sample aggregate together as opposed to remaining as individual, isolated particles: L, S (Liquid, Solid) f. The sample has a definite shape and a fixed volume: S (Solid) g. The sample has a variable shape and a mostly fixed volume: L (Liquid) h. The sample has an indefinite shape and an indefinite volume: G (Gas) i. Intermolecular forces are abnormally strong: S (Solid) 7. In comparing two or more liquid substances, the substance which has the greater intermolecular forces will tend to have... (CIRCLE one of the terms in parentheses.) a. higher boiling point b. lower rate of evaporation c. lower vapor pressure d. higher viscosity e. stronger surface tension 8. Which has the lowest vapor pressure? H₂O (Hydrogen bonding) I₂ (Dipole-dipole) NH₃ (Hydrogen bonding) CO₂ (Dipole-dipole) CH₄ (Dispersion forces) Answer: CH₄ (Weakest IMF) 9. Which of the following should have the lowest boiling point? CH₄ C₂H₆ C₃H₈ C₄H₁₀ C₅H₁₂ Answer: CH₄ (Smallest, least # of e-) 10. Fill in the chart below: Phase Change Initial State → Final State Is energy absorbed (endothermic) or Released (exothermic)? Condensation g → l exothermic Melting s → l endothermic Vaporization l → g endothermic Freezing l → s exothermic Sublimation s → g endothermic Deposition g → s exothermic Use the data table or graph below to answer the following questions. 11. Which molecule shown on the graph possesses the strongest IMFs? C12H26 12. How did you determine your choice? Give 2 reasons. a. Highest b.p. & m.p. (trend in data table) b. Largest # of atoms = more e- 13. Which state of matter has stronger IMFs - liquids or gases? Explain how this is proven by the data below. Liquids have stronger IMFs than gases. This is proven by the data because: Liquids take more energy to boil AND have greater molecular weight.