AP Chemistry - Problem Drill 17: Liquids and Solids No. 1 of 10 Instruction: (1) Read the problem statement and answer choices carefully (2) Work the problems on paper as 1. What intermolecular forces does H 2 O exhibit? A. London Dispersion Forces B. Dipole-Dipole Forces C. Hydrogen Bonding D. All of the above E. None of the above A. Incorrect. Water does have London Dispersion Forces, but there are also other intermolecular forces. Water does have Dipole-Dipole Forces, but there are also other intermolecular forces. Water does have Hydrogen Bonding Forces, but there are also other intermolecular forces. D. Correct. Water does have London Dispersion Forces, but there are also other intermolecular forces. E. Incorrect. Look closely water does have one or more of the intermolecular forces listed. All molecules exhibit London Dispersion Forces. Water is a polar molecule with two hydrogen atoms bonded to a highly electronegative atom (oxygen). The asymmetrical distribution of lone pair electrons of oxygen combines with the asymmetrical distribution of the polar H-O bonds to give the water molecule a dipole, while polar H-O bonds enable hydrogen bonding. The correct answer is.
No. 2 of 10 2. How is vapor pressure affected by an increase of temperature? Vapor Pressure is increased. Vapor Pressure is decreased. Vapor Pressure remains the same. There is not predictable pattern. It depends on which liquid is being studied. A. Correct. As temperature increases, the number of atoms with the minimum energy to vaporize increases. As temperature increases, the number of atoms with the minimum energy to vaporize increases. As temperature increases, the number of atoms with the minimum energy to vaporize increases. As temperature increases, the number of atoms with the minimum energy to vaporize increases. E. Incorrect. All liquids have the same relationship between temperature and vapor pressure. As temperature increases, the number of atoms with the minimum energy to vaporize increases. Vapor pressure increases. The correct answer is.
No. 3 of 10 3. Which phase change requires breaking all the intermolecular forces? Melting Freezing Condensing Subliming Depositing A. Incorrect. Melting requires the breaking of some intermolecular forces, but some remain. Freezing requires the formation of intermolecular forces. Condensing requires the formation of intermolecular forces. D. Correct. Subliming requires the breaking of all intermolecular forces. E. Incorrect Depositing requires forming intermolecular forces. All of the intermolecular forces are broken when a gas is produced, (as long as the gas obeys the Ideal Gas Law). Choice A & C produce liquids and Choice B produces a solid. The correct answer is.
No. 4 of 10 4. A compound s boiling point is the point at which and are equal? Liquid s vapor pressure & atmospheric pressure. Gas s vapor pressure & atmospheric pressure. Liquid s vapor pressure & solid s vapor pressure. Liquid s vapor pressure & gas s vapor pressure. Gas s vapor pressure & solid s vapor pressure. A. Correct. E. Incorrect! The correct answer is.
No. 5 of 10 5. Which is a WRONG match? Metallic solid metal atoms in closest packing with electrons in a large pool. Network solid closest packing of non-metal atoms with only physical attractions between atoms. Molecular solid covalent bonding within molecules with only physical attractions between molecules. Ionic Solid Closest packing of ions that minimizes like-charged ion repulsions. All of the pairings are correct. A. Incorrect. Metallic bonding is metal atoms, closest packing, pool of electrons. B. Correct. Network bonding is non-metals atoms covalently bonded to the neighboring atoms, not non-metal atoms with only physical attractions. Molecular solids are covalent bonds within the molecules and physical IMF between them. Ionic solids are closest packing of ions to minimize like-charge repulsions. E. Incorrect. Look closely there is an incorrect pairing. All of the pairings are correct except for the network solid. Network solids are not non-metal atoms with physical attractions, they are non-metals atoms that are covalently bonded to the neighboring atoms. The correct answer is.
No. 6 of 10 6. If 825 J are needed to melt a sample of ice, what mass was the sample? The heat of fusion of ice is 334 J/g. The heat of vaporization of ice is 2287 J/g. 2.47 g 0.405 g 0.361 g 2.77 g 276 kg A. Correct. You correctly solved for mass. Check your algebra. Check your algebra. Check your algebra. E. Incorrect! Check your algebra. ΔH = 825 J H fus = 334 J/g H vap = 2287 J/g m =? g For melting, use enthalpy of fusion Δ H = m H fus 825 J = m 334 J g 825J 334 J g = m m = 2.47 g The correct answer is.
No. 7 of 10 7. Which intermolecular force is not important for C 3 H 8? London Dispersion Forces Dipole-Dipole forces Hydrogen bonding A & C B & C A: Incorrect. This molecule does have London dispersion forces. B: Incorrect. This molecule does not have dipole-dipole forces, but there is another one as well. C: Incorrect. This molecule does not have hydrogen-bonding, but there is another one as well. D: Incorrect. This molecule does have London dispersion forces. E. Correct! This molecule does not have dipole intermolecular forces or hydrogen bonding. This nonpolar molecule has only London Dispersion intermolecular forces. Both dipole-dipole interactions and hydrogen bonding are not important with this molecule. The correct answer is.
No. 8 of 10 8. Which molecules cause vapor pressure? Molecules at the surface. Molecules at the surface that break intermolecular forces to evaporate. Air above the surface of the container. Any molecule in the container that breaks intermolecular forces to evaporate. It depends on which liquid is being studied. A. Incorrect. Molecules at the surface can only vaporize if they have the minimum energy to break intermolecular forces. B. Correct. Molecules at the surface can only vaporize if they have the minimum energy to break intermolecular forces. Air above the surface causes pressure, but we call it atmospheric pressure instead of vapor pressure. Only molecules on the surface can vaporize. E. Incorrect! This answer does not depend on the identity of the liquid. Only molecules at the surface can break intermolecular forces to evaporate. The correct answer is.
No. 9 of 10 9. Which forces are present in CH 3 F? London Dispersion Forces. London Dispersion Forces & Dipole-dipole. London Dispersion Forces & Hydrogen-bonding. London Dispersion Forces, Dipole-Dipole and Hydrogen bonding. No intermolecular forces. A. Incorrect. This molecule does have London Dispersion Forces, but also another one. B. Correct. This molecular is polar. This molecule cannot hydrogen bond. This molecule cannot hydrogen bond. E. Incorrect! All molecules have intermolecular forces. CH 3 F is a polar molecule, but the hydrogen atoms are bonded to the carbon and therefore cannot hydrogen bond. The correct answer is.
No. 10 of 10 10. Which intermolecular force is larger for C 3 H 8 than for CH 4? London Dispersion Forces. Dipole-Dipole forces. Hydrogen bonding. All forces are the same for these two molecules. All intermolecular forces are larger for C 3 H 8. A. Correct. As size of molecule increases, London Dispersion Forces increases. Neither molecule is polar. Neither molecule can hydrogen bond. There is a difference in the intermolecular forces of these two molecules. E. Incorrect! Only one of the intermolecular forces is greater in this problem. The larger the molecule, the more electrons there are to gang-up on one side and cause a temporary dipole. The correct answer is.