Q: Determine the amount of heat, in kJ, required to vaporize 1.55 kg of water at its boiling point. $$\Delta H_{vap} of $$water at 100$$^\circC is 40.7 kJ/$$mol.

$$3.50 \times 10^3$\ \text{kJ}$$

Question 1

Which of the following best describes the Lewis structure for ozone, O$$_3$$?

Accepted Answer

One single bond, one double bond and six lone pairs of electrons

Question 2

Which of the following species are exceptions to the octet rule?

Accepted Answer

BF$$_3$$ and SF$$_4$$

Question 3

Using the provided electronegativity table, which bond is the most polar?

Accepted Answer

C–O

Question 4

Which statement about the electronegativity scale is FALSE?

Accepted Answer

Ionic bonding occurs between atoms of similar electronegativity.

Question 5

Select the FALSE statement.

Accepted Answer

In a C–Br bond, the negative end of the dipole is on the C.

Question 6

Given the bond length and bond energy data, which statement is TRUE?

Accepted Answer

X–A is a longer bond than X–B and X–A is a weaker bond than X–C.

Question 7

Which of the following statements about bond order and bond strength is FALSE?

Accepted Answer

Breaking bonds is always an exothermic process.

Question 8

Using the bond energies given, calculate $$\Delta H_{rxn}$$ for the reaction: $$\ce{C2H6 + 5 S2 -\u003e 3 C2S + 4 H2S} ($$see image).

Accepted Answer

$$-1207\ 	ext{kJ/mol}$$

Question 9

In the best Lewis structure for ICl$$_4^-$$, what are the electron geometry and the molecular shape around the central iodine atom?

Accepted Answer

Electron geometry: Octahedral; Molecular shape: Square planar

Question 10

What are the bond angles indicated by $$\alpha$$ and $$\beta in $$the structure shown (see image)?

Accepted Answer

$$\alpha = 120^\circ$$, $$\beta = 180^\circ$$

Question 11

What is the hybridization on the atoms labelled 1, 2, and 3 in the caffeine structure (see image)?

Accepted Answer

1: sp$$^2$$, 2: sp$$^3$$, 3: sp$$^2$$

Question 12

Which of the following molecules contains polar bonds but is NOT a polar molecule?

Accepted Answer

SiF$$_4$$

Question 13

How many $$\sigma$$ and $$\pi$$ bonds are present in the structure for caffeine (see image)?

Accepted Answer

21 $$\sigma$$, 4 $$\pi$$

Question 14

Which of the following contains dipole-dipole forces?

Accepted Answer

H$$_2O $$and SBr$$_4$$

Question 15

Determine the amount of heat, in kJ, required to vaporize 1.55 kg of water at its boiling point. $$\Delta H_{vap} of $$water at 100$$^\circC is 40.7 kJ/$$mol.

Accepted Answer

$$3.50 	imes 10^3$\ 	ext{kJ}$$

Question 16

The normal boiling point of Br$$_2(l) is 332 K. At 283 K$$, the vapor pressure of Br$$_2(l) is 0.144 $$atm. What is its enthalpy of vaporization?

Accepted Answer

$$30.9\ 	ext{kJ/mol}$$

Question 17

Which type of intermolecular forces are present in ALL pure liquid substances?

Accepted Answer

dispersion

Question 18

Which arrow in the phase diagram (see image) represents condensation?

Accepted Answer

C

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