4.16 - Intermolecular Forces - 2015 - Quiz, Flashcards & Trivia

1. At standard pressure, HF and NH3 have higher boiling points than HBr and CH4 do. What accounts for the higher boiling point of HF?

NH3 and HF have higher boiling points, because they contain London Forces.

NH3 and HF have higher boiling points, because they contain hydrogen bonds.

NH3 and HF have higher boiling points, because they contain dipole-dipole forces.

NH3 and HF have higher boiling points, because they contain ion-dipole forces.

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest). NH3 and HF have hydrogen bonding because they have H-F/H-O/H-N bonded. HBr is polar, so it's just dipole-dipole. CH4 is nonpolar, so it's London Dispersion Forces. Hydrogen Bonds are stronger IMF's than dipole-dipole and London Forces are, so NH3 and HF have higher boiling points as a result.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest). NH3 and HF have hydrogen bonding because they have H-F/H-O/H-N bonded. HBr is polar, so it's just dipole-dipole. CH4 is nonpolar, so it's London Dispersion Forces. Hydrogen Bonds are stronger IMF's than dipole-dipole and London Forces are, so NH3 and HF have higher boiling points as a result.

2. Which element combines with hydrogen to form a compound with the strongest hydrogen bonding between its molecules?

Sulfur

Tellurium

Selenium

Oxygen

H-O, H-N, H-F=Hydrogen Bonds (Weaker than Ion-dipole forces). H and O makes an H-O bond, so the IMF's between the molecules are hydrogen bonding.

Explanation

H-O, H-N, H-F=Hydrogen Bonds (Weaker than Ion-dipole forces). H and O makes an H-O bond, so the IMF's between the molecules are hydrogen bonding.

3. At standard pressure, HF has a higher boiling point than HCl, HBr, or H2 does. What accounts for the higher boiling point of HF?

HF has a higher boiling point, because it contains London forces.

HF has a higher boiling point, because it contains hydrogen bonds.

HF has a higher boiling point, because it contains dipole-dipole forces.

HF has a higher boiling point, because it contains ion-dipole forces.

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest). HF has H-F, so it has hydrogen bonding. HCl and HBr are polar molecules (asymmetrical distribution of charge) without H-F, H-N, or H-O, so they have dipole-dipole forces. H2 is a nonpolar molecule (symmetrical distribution of charge), so it has London forces. Hydrogen bonding in H-F is the strongest IMF (stronger than dipole-dipole and London forces), so HF will have the highest boiling point, because it has the strongest IMF's of the four molecules.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest). HF has H-F, so it has hydrogen bonding. HCl and HBr are polar molecules (asymmetrical distribution of charge) without H-F, H-N, or H-O, so they have dipole-dipole forces. H2 is a nonpolar molecule (symmetrical distribution of charge), so it has London forces. Hydrogen bonding in H-F is the strongest IMF (stronger than dipole-dipole and London forces), so HF will have the highest boiling point, because it has the strongest IMF's of the four molecules.

4. At standard pressure, NH3 has a boiling point of 240 K, AsH3 has a boiling point of 211 K, and PH3 has a boiling point of 186 K. What accounts for the higher boiling point of NH3?

NH3 has a higher boiling point, because it contains London forces.

NH3 has a higher boiling point, because it contains hydrogen bonds.

NH3 has a higher boiling point, because it contains dipole-dipole forces.

NH3 has a higher boiling point, because it contains ion-dipole forces.

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding; Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest). NH3 has H-N, so it has hydrogen bonding. AsH3 and PH3 are polar molecules (asymmetrical distribution of charge) without H-O, N-H, and H-F, so they have dipole-dipole forces. Hydrogen bonding is stronger than dipole-dipole forces are, so NH3 has the highest boiling point, because it has the strongest IMF's out of the three molecules.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding; Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest). NH3 has H-N, so it has hydrogen bonding. AsH3 and PH3 are polar molecules (asymmetrical distribution of charge) without H-O, N-H, and H-F, so they have dipole-dipole forces. Hydrogen bonding is stronger than dipole-dipole forces are, so NH3 has the highest boiling point, because it has the strongest IMF's out of the three molecules.

5. Substance A has a boiling point of 13 degrees Celsius, Substance B has a boiling point of 20 degrees Celsius, Substance C has a boiling point of 23 degrees Celsius, Substance D has a boiling point of 12 degrees Celsius. Which substance has the strongest intermolecular forces?

Substance A

Substance B

Substance C

Substance D

Higher Boiling Point=Stronger Intermolecular Forces.

Explanation

Higher Boiling Point=Stronger Intermolecular Forces.

6. Based on the ion shown, which side of water molecules should be touching the ion?

None of the above

The partial positive end of water molecules (H end) is attracted to the negative ion. The partial negative end of water molecules (O end) is attracted to the positive ion. This is because opposites attract.

Explanation

The partial positive end of water molecules (H end) is attracted to the negative ion. The partial negative end of water molecules (O end) is attracted to the positive ion. This is because opposites attract.

7. A mixture contains hydrogen fluoride and ammonia. Identify a strong intermolecular force of attraction between hydrogen fluoride and ammonia.

Dipole-Dipole Forces

Hydrogen Bonding

Ion-Dipole Forces

London Dispersion Forces

H-O, H-N, H-F=Hydrogen Bonds (Weaker than Ion-dipole forces). Both hydrogen fluoride (HF) and ammonia (NH3) contain H-F, H-O, or H-N bonds, so the IMF's between them are hydrogen bonds.

Explanation

H-O, H-N, H-F=Hydrogen Bonds (Weaker than Ion-dipole forces). Both hydrogen fluoride (HF) and ammonia (NH3) contain H-F, H-O, or H-N bonds, so the IMF's between them are hydrogen bonds.

8. Determine the main type of intermolecular forces in C2H5OH.

London Dispersion Forces

Ion-Dipole Forces

Dipole-Dipole Forces

Hydrogen Bonds

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces. Since C2H5OH has O directly bonded to H somewhere in the molecule, based on the definition of hydrogen bonding, this qualifies as having hydrogen bonds.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces. Since C2H5OH has O directly bonded to H somewhere in the molecule, based on the definition of hydrogen bonding, this qualifies as having hydrogen bonds.

9. Determine the main type of intermolecular forces in CaO (aq).

London Dispersion Forces

Ion-Dipole Forces

Dipole-Dipole Forces

Hydrogen Bonds

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces. Since CaO (aq) has an ionic compound, the CaO part, and water, the (aq) part, this qualifies as having ion-dipole forces.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces. Since CaO (aq) has an ionic compound, the CaO part, and water, the (aq) part, this qualifies as having ion-dipole forces.

10. At standard pressure, H2Se and CO have higher boiling points than CF4 and CO2 do. What accounts for the higher boiling point of HF?

H2Se and CO have higher boiling points, because they contain London Forces.

H2Se and CO have higher boiling points, because they contain hydrogen bonds.

H2Se and CO have higher boiling points, because they contain dipole-dipole forces.

H2Se and CO have higher boiling points, because they contain ion-dipole forces.

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding
Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest). H2Se and CO have dipole-dipole forces because they are polar molecules without H-F/H-O/H-N. CF4 and CO2 are both nonpolar, so they have London Dispersion Forces. Dipole-Dipole Forces are stronger IMF's than London Forces are, so H2Se and CO have higher boiling points as a result.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding
Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest). H2Se and CO have dipole-dipole forces because they are polar molecules without H-F/H-O/H-N. CF4 and CO2 are both nonpolar, so they have London Dispersion Forces. Dipole-Dipole Forces are stronger IMF's than London Forces are, so H2Se and CO have higher boiling points as a result.

11. Rank the following molecules in order of increasing boiling point: CH3Cl, CH3OH, Na2O (aq), CF4.

CF4 < CH3OH < CH3Cl < Na2O (aq)

CF4 < CH3Cl < CH3OH < Na2O (aq)

CF4 < Na2O (aq) < CH3Cl < CH3OH

CF4 < Na2O (aq) < CH3OH < CH3Cl

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest IMF's, lowest boiling point); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding; Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest IMF's, highest boiling point). CF4 is nonpolar (symmetrical distribution of charge), so it has London forces. CH3Cl is a polar molecule (asymmetrical distribution of charge) without H-F, H-O, or H-N, so it has dipole-dipole forces. CH3OH has O-H in its structure, so it has hydrogen bonding. Na2O (aq) has an ionic compound, Na2O, dissolved in water (aq), so it has ion-dipole forces. In order, London forces are weakest, dipole-dipole forces are stronger, hydrogen bonds are even stronger than dipole-dipole, and ion-dipole forces are strongest.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest IMF's, lowest boiling point); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding; Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest IMF's, highest boiling point). CF4 is nonpolar (symmetrical distribution of charge), so it has London forces. CH3Cl is a polar molecule (asymmetrical distribution of charge) without H-F, H-O, or H-N, so it has dipole-dipole forces. CH3OH has O-H in its structure, so it has hydrogen bonding. Na2O (aq) has an ionic compound, Na2O, dissolved in water (aq), so it has ion-dipole forces. In order, London forces are weakest, dipole-dipole forces are stronger, hydrogen bonds are even stronger than dipole-dipole, and ion-dipole forces are strongest.

12. Determine the main type of intermolecular forces in CCl4.

London Dispersion Forces

Ion-Dipole Forces

Dipole-Dipole Forces

Hydrogen Bonds

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces. Since CCl4 is nonpolar (symmetrical distribution of charge overall), this qualifies as having London Dispersion Forces.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding;
Saltwater (ionic compound and water)=Ion-Dipole Forces. Since CCl4 is nonpolar (symmetrical distribution of charge overall), this qualifies as having London Dispersion Forces.

13. Rank the following molecules in order of increasing boiling point: NaF (aq), H2S, HF, CO2.

NaF (aq) < H2S < HF < CF4

H2S < CO2 < HF < NaF (aq)

CO2 < H2S < HF < NaF (aq)

CO2 < HF < H2S < NaF (aq)

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest IMF's, lowest boiling point); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding; Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest IMF's, highest boiling point). CO2 is nonpolar (symmetrical distribution of charge), so it has London forces. H2S is a polar molecule (asymmetrical distribution of charge) without H-F, H-O, or H-N, so it has dipole-dipole forces. HF has F-H in its structure, so it has hydrogen bonding. NaF (aq) has an ionic compound, NaF, dissolved in water (aq), so it has ion-dipole forces. In order, London forces are weakest, dipole-dipole forces are stronger, hydrogen bonds are even stronger than dipole-dipole, and ion-dipole forces are strongest.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest IMF's, lowest boiling point); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding; Saltwater (ionic compound and water)=Ion-Dipole Forces (strongest IMF's, highest boiling point). CO2 is nonpolar (symmetrical distribution of charge), so it has London forces. H2S is a polar molecule (asymmetrical distribution of charge) without H-F, H-O, or H-N, so it has dipole-dipole forces. HF has F-H in its structure, so it has hydrogen bonding. NaF (aq) has an ionic compound, NaF, dissolved in water (aq), so it has ion-dipole forces. In order, London forces are weakest, dipole-dipole forces are stronger, hydrogen bonds are even stronger than dipole-dipole, and ion-dipole forces are strongest.

14. Determine the main type of intermolecular forces in PH3.

London Dispersion Forces

Ion-Dipole Forces

Dipole-Dipole Forces

Hydrogen Bonds

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding; Saltwater (ionic compound and water)=Ion-Dipole Forces. Since PH3 is a polar molecule (it's asymmetrical overall, in terms of charge distribution) without H-F, H-O, or H-N, this qualifies as having dipole-dipole forces.

Explanation

Nonpolar Molecules (Symmetrical distribution of charge)=London Dispersion (weakest); Polar Molecules (Asymmetrical distribution of charge)=Dipole-Dipole Forces; Molecules with H-F, H-O, or H-N (because of big ∆EN)=Hydrogen Bonding; Saltwater (ionic compound and water)=Ion-Dipole Forces. Since PH3 is a polar molecule (it's asymmetrical overall, in terms of charge distribution) without H-F, H-O, or H-N, this qualifies as having dipole-dipole forces.

15. Compounds like CuO and NaHCO3 are soluble in water. Compare the boiling point of a solution of CuO to the boiling point of water at standard pressure.

The solution of CuO has a higher boiling point than water does.

Water has a higher boiling point than the CuO solution does.

Ionic Compound + Water=Ion-Dipole Forces (strongest IMF's); H-O, H-N, H-F=Hydrogen Bonds (Weaker than Ion-dipole forces); CuO in water is an ionic compound in water, so it has ion-dipole forces. On the other hand, water has H-O, so it has hydrogen bonding. Ion-dipole has stronger IMF's and, therefore, a higher boiling point.

Explanation

Ionic Compound + Water=Ion-Dipole Forces (strongest IMF's); H-O, H-N, H-F=Hydrogen Bonds (Weaker than Ion-dipole forces); CuO in water is an ionic compound in water, so it has ion-dipole forces. On the other hand, water has H-O, so it has hydrogen bonding. Ion-dipole has stronger IMF's and, therefore, a higher boiling point.