Comparing Intermolecular Force’s

1. Comparing Intermolecular Force’s

2. Comparing Intermolecular Force’s • In general, the strengths of the intermolecular forces are ranked as follows: Hydrogen bonds > dipole-dipole forces > London Dispersion Forces • For similar molecules, the strength of the intermolecular forces increases as the mass of the molecule increases. IMF of HCl < IMF of HBr < IMF of HI GFM = 36.5 g/mol GFM = 81 g/mol GFM = 128 g/mol

3.           H H H H H S S S S S           H H H H H   H S H   Comparing Intermolecular Force’s Ex. (1) What type of intermolecular force exists between the molecules of liquid hydrogen sulfide (H2S)? _____________________ dipole-dipole forces

4.                               Br Br Br Br Br Br Br Br Br Br Br Br                                                Br Br        Comparing Intermolecular Force’s Ex. (2) What type of intermolecular force exists between the molecules of liquid bromine (Br2)? ______________________ London dispersion forces

5.               H Cl  H H H H H H Cl Cl Cl Cl Cl Cl                            Comparing Intermolecular Force’s Ex. (3) What type of intermolecular force exists between the molecules of liquid hydrogen chloride (HCl)? _____________________ dipole-dipole forces

6.           O O O O H H H H H O             H O H H H H H H   Comparing Intermolecular Force’s Ex. (4) What type of intermolecular force exists between the molecules of liquid water (H2O)? ______________________ hydrogen bonding forces

7.    Ne                            Ne Ne Ne Ne Ne Ne Ne Ne                                           Comparing Intermolecular Force’s Ex. (5) What type of intermolecular force exists between the molecules of liquid neon (Ne)? ______________________ London dispersion forces

8.             H N H H H H H H N N N N N H H H H H H H H H H H Comparing Intermolecular Force’s Ex. (6) What type of intermolecular force exists between the molecules of liquid ammonia (NH3)? ______________________ hydrogen bonding forces

9. H H H H H H H C H H H H H H C C C C C H H H H H H H H H H H Comparing Intermolecular Force’s Ex. (7) What type of intermolecular force exists between the molecules of liquid methane (CH4)? ______________________ London dispersion forces

10.   H F                 H H H H H H F F F F F F                         Comparing Intermolecular Force’s Ex. (8) What type of intermolecular force exists between the molecules of liquid hydrogen fluoride (HF)? ______________________ hydrogen bonding forces

11.                                    I I I I I I I I I I I I I I                                                  Comparing Intermolecular Force’s Ex. (9) What type of intermolecular force exists between the molecules of solid iodine (I2)? ______________________ London dispersion forces

12. O O O O O O O C C C C C C C O O O O O O O • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Comparing Intermolecular Force’s Ex. (10) What type of intermolecular force exists between the molecules of solid carbon dioxide (CO2)? ______________________ London dispersion forces

13. Ne(l) Ar(l) Kr(l) Xe(l) Comparing Intermolecular Force’s Ex. (11) Which of the following liquid samples would have the lowest boiling point and why? They are all noble gases. Noble gases have spherical shapes. Noble gases are symmetrical molecules. Symmetrical molecules are nonpolar molecules. Nonpolar molecules exhibit London dispersion forces. London dispersion forces are weakest between the least massive molecules. ________________________________________ ________________________________________ Nebecause it has the weakest London dispersion forces between its lowest mass molecules.

14. H2Se(l) H2Te(l) H2S(l) Comparing Intermolecular Force’s Ex. (12) Which of the following liquid samples would have the lowest boiling point and why? They are all similar molecules from Group-16 . They all have bent shapes. Bent shaped molecules are asymmetrical molecules. Asymmetrical molecules are polar molecules. Polar molecules exhibit dipole-dipole forces. Dipole-dipole forces are strongest between the most massive molecules. ________________________________________ ________________________________________ H2S because it exhibits the weakest dipole-dipole forces due to its lowest mass.

15. H2O(l) H2S(l) H2Se(l) H2Te(l) Comparing Intermolecular Force’s Ex. (13) Which of the following liquid samples would have the highest boiling point and why? They are all similar molecules from Group-16 . They all have bent shapes. Bent shaped molecules are asymmetrical. Asymmetrical molecules are polar molecules. Polar molecules exhibit dipole-dipole forces. Dipole-dipole forces are strongest between the most massive molecules. ______________________________________________ _______________________________________ _______________________________________ H2O because it exhibits hydrogen bonding which is stronger than the dipole-dipole forces exhibited in the other samples.

16. F2(l) Cl2(l) Br2(l) I2(l) Comparing Intermolecular Force’s Ex. (14) Which of the following liquid samples would have the highest boiling point and why? They are all group-17 diatomic free elements. They all have linear shapes. They are all symmetrical molecules. Symmetrical molecules are nonpolar molecules. Nonpolar molecules exhibit London dispersion forces. London dispersion forces are strongest between the most massive molecules. _______________________________________________ _______________________________________________ I2because it has the strongest London dispersion forces between its highest mass molecules.

17. NH3(l) PH3(l) AsH3(l) SbH3(l) Comparing Intermolecular Force’s Ex. (15) Which of the following liquid samples would have the highest boiling point and why? They are all similar molecules from Group-15 . They all have pyramidal shapes. Pyramidal shaped molecules are asymmetrical. Asymmetrical molecules are polar molecules. Polar molecules exhibit dipole-dipole forces. Dipole-dipole forces are strongest between the most massive molecules. ______________________________________________ ______________________________________________ ______________________________________________ NH3 because it exhibits the stronger hydrogen bonding whereas the others only exhibit dipole- dipole forces.

18. H H H H C C C H H H H C H • • • • H Comparing Intermolecular Force’s Ex. (16) A liquid sample of which of the following molecular substances would have the higher boiling point and why? _______________________________________ _______________________________________ _______________________________________ _______________________________________ H H bp = 56oC Both have the same mass! (58 g/mol) H C C C H H O H bp = -12oC Both molecules exhibit dipole-dipole forces. The sample of the molecules on the left would have the higher boiling point due to their greater degree of polarity than the molecules on the right.