depphead (depphead) wrote in chemistree,
depphead
depphead
chemistree

AP Chem

I'm working on a take home test for Chemistry and there are a few questions I'm a little unsure about, if someone could help explain any of them to me I would really appreciate it...

1.) Which of the following would you expect to have the highest boiling point?
[A] Cl2
[B] I2
[C] F2
[D] Br2
[E] All of these have the same boiling point.

2.) Which of the following is the correct order of boiling points for KNO3, CH3OH, C2H6, Ne from lowest to highest?
[A] Ne, C2H6, CH3OH, KNO3
[B] Ne, C2H6, KNO3, CH3OH
[C] C2H6, Ne, CH3OH, KNO3
[D] KNO3, CH3OH, C2H6, Ne
[E] Ne, CH3OH, C2H6, KNO3

3.) The molecules in a sample of solid SO2 are attracted to each other by a combination of:
[A] London forces and H-bonding
[B] H-bonding and ionic bonding
[C] London forces and dipole-dipole interactions
[D] Covalent bonding and dipole-dipole interactions
[E] none of these

4.) Knowing that ΔHvap for water is 40.7 kJ/mol, calculate Pvap of water at 37°C.
[A] 25.4 torr
[B] 52.6 torr
[C] 12.4 torr
[D] 18.7 torr
[E] 6.90 torr


5.) The molar volume of a certain form of solid lead is 18cm3/mol. Assuming cubic closest packed structure, determine the radius of a Pb atom:
[A] 1740 pm
[B] 174 pm
[C] 17.4 pm
[D] 1.74 pm
[E] none of these

6.) When a water molecule forms a hydrogen bond with another water molecule, which atoms are involved in the interaction?

7.) Sodium Oxide (Na2O) crystallizes in a structure in which the O2- ions are in a face-centered cubic lattice and the Na+ ions are in tetrahedral holes. The number of Na+ ions in the unit cell is:
[A] 8
[B] 4
[C] 2
[D] 6
[E] none of these

8.) Aluminum metal crystallizes in a face-centered cubic structure. The relationship between the radius of an Al atom (r) and the length of an edge of the unit cell (E) is:
[A] r = E/2
[B] r = 2E
[C] r = (√3/4)E
[D] r = 4E
[E] r = (√2/4)E

9.) The vapor pressure of water at 25°C is 23.8 torr; ΔHvapor = 43.9 kJ/mol.
a. Determine the vapor pressure of water at 70°C.
b. Determine the percentage error if your experimental results for vapor pressure at 70°C give a result of 225 torr.
c. Give structural reasons that support the fact that the boiling temperature of C2H3OH is 78°C and water is 100°C (both at 760 torr).

NOTE: I'm not just posting my whole test on here, I just numbered them so the post is easier to read.

Any help is appreciated.
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