Lehman College of the City University of New York Department of Chemistry Paraff

Question

Lehman College of the City University of New York Department of Chemistry Paraffin wax has the chemical formula Ca1Hs4 and has no dipole moment Paraffin is a solid at a. The IMFs in paraffin are stronger than the IMFs in water. The only IMFs in paraffin are room temperature but water is a liquid. These phase differences are best explained by: weak London dispersion forces but paraffin is such a large molecule that the sum of the weak LDFs is greater than the hydrogen bonding in water. b. The IMFs in paraffin are weaker than the IMFs in water making paraffin a solid at room temperature and making water a liquid because water is so much smaller c. The IMFs in paraffin are weaker than the IMFs in water. Paraffin should therefore be a liquid but it is an anomaly in chemistry d. The IMFs in paraffin are stronger than the IMFs in water. Paraffin has many more hydrogens than water and forms many strong hydrogen bonds. 16)The molecular model to the right represents the bonding in a AB2Ca molecule corresponding to the accompanying Lewis structure. The B atoms are in the axial position and the C atoms are in the equatorial position. For this molecule the B-A-C bond angle is and the C-A-C bond angle is a. exactly 90°, slightly less than 120 b. slightly less than 90, exactly 120 c. exactly 90°, exactly 120 d. slightly less than 90°, slightly less than 120°

Explanation / Answer

ANSWER:

Q15. The IMFs in parafin are weak London forces, and in water there exist hydrogen bonding. Hydrogen bonding is stronger than London forces. But the magnitude of London forces is directly proportional to the size of molecule. Since parafin is large molecule so the resultant LDFs are stronger than hydrogen bonds in water. Hence option (A) is the correct answer.

Q16:

The structure is trigonal bipyramidal. B atoms are in axial position making B-A-B angle 180o. The C atoms are in equitorial position i.e at right angle to B-A-B axis. Thus the B-A-C bond angle is 90o. The C-A-C angle is 120o.

Hence option (c) is correct answer.

Related Questions

Navigate

• Browse (All)
• Browse L
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.