1. HW 10-4

2. HW 10-4 > > 1A) Rank IMF’s according to relative strength
1B) What factor can significantly change the relative strength of LDF?
1C) The greater the strength of the intermolecular forces between molecules the the boiling point.
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Hydrogen Bonding
Dipole- Dipole
LDF
SIZE OF ELECTRON CLOUD;
LARGER CLOUD = STRONG LDF
HIGHER

3. HW 10-4, #2 – Strongest IMF – flow chart
YES; ANS = HYDROGEN BOND
Is there a hydrogen bond? (H and HFON) NO
Do BOTH molecules have a net dipole?
YES; ANS = DIPOLE-DIPOLE
NO; ANS = LDF

4. HW 10-4, #2 – Strongest IMF LDF; H2 is nonpolar (no FON to H-bond)
A) H2 and H2O B) NH3 and H2O
LDF; H2 is nonpolar (no FON to H-bond)
HYDROGEN BONDING ; BOTH HAVE HFON

5. HW 10-4, #2 – Strongest IMF
C) BH2F and BH2F

6. HW 10-4, #2 – Strongest IMF
C) BH2F and BH2F
DIPOLE- DIPOLE

7. HW 10-4, #2 – Strongest IMF
D) BF3 and BF3
LDF; BF3 is nonpolar (no H to H-bond); symmetric trigonal planar structure

8. HW 10-4, #2 – Strongest IMF LDF; Both are nonpolar
E) NH3 and CH3OH F) He and CH4
HYDROGEN BONDING ; BOTH HAVE HFON

9. HW 10-4, #3 – Explain Observations in terms of IMF’s
A) I2 has a higher boiling point than Br2.
Strongest type of IMF between I2 molecules:
Strongest type of IMF between Br2 molecules:
Explanation:
LDF; nonpolar
LDF; nonpolar
Both are LDF; however strength of LDF depends on size of e- cloud. I2 is farther down family; extra electron levels = bigger atom and stronger LDF

10. HW 10-4, #3 – Explain Observations in terms of IMF’s
B) H2O has a higher boiling point than H2S.
Strongest type of IMF between H2O molecules:
Strongest type of IMF between H2S molecules:
Explanation:

11. HW 10-4, #3 – Explain Observations in terms of IMF’s
B) H2O has a higher boiling point than H2S.
Strongest type of IMF between H2O molecules:
Strongest type of IMF between H2S molecules:
Explanation:
Hydrogen bonding;
Dipole-dipole
Hydrogen bonding is stronger than dipole-dipole H-O is more polar than H-S bond

12. HW 10-4, #4 – Rank from highest to lowest bp based on IMF’s
LDF; nonpolar
Strongest type of IMF between H2 molecules:
Strongest type of IMF between HF molecules:
Strongest type of IMF between HCl molecules:
Hydrogen bonding;
Dipole-dipole
HF > HCl > H2