1. Which is the most electronegative atom?

(A) P
(B) Al
(C) Cl
(D) S

2. The closest verbal description of the shape of the NH₃ molecule (defined by the positions of the atomic nuclei) is

(A) tetrahedral
(B) non-linear
(C) trigonal planar
(D) trigonal pyramid

3. Which of these molecules is octahedral?

(A) SF₄
(B) SF₆
(C) ClF₃
(D) BrF₅

4. Given the reactions

CH4(g) + 2O2(g) -----> CH2O (g) + 2H2O(g)	DH° = -890.4 kJ
CH2O(g) + O2(g) -----> CO2(g) + H2O(g)	DH° = -563.5 kJ

what is DH° for the reaction

CH₄(g) + O₂(g) ----> CO₂(g) + H₂O(g)?

(A) -1453.9 kJ
(B) -326.9 kJ
(C) -236.6 kJ
(D) +118.3 kJ

5. 500 mL of a gaseous compound weighs 0.9825 gram at 0 °C and 760 torr. What is the approximate molecular weight of the compound in g/mol?

(A) 19.7
(B) 38. 7
(C) 44.0
(D) 58.9

6. What is the number of molecules in 1.00 mL of an ideal gas at STP?

(A) 2.69 x 10²²
(B) 6.02 x 10²⁰
(C) 2.69 x 10¹⁹
(D) 22.4 x 10¹⁹

7. If 6.60 g of a gaseous compound occupy a volume of 1.20 L at 27 °C and 0.967 atm, the molecular weight of the compound is

(A) 109 g/mol.
(B) 123 g/mol.
(C) 140 g/mol.
(D) 165 g/mol.

8. How many liters of hydrogen gas at STP can be produced by the reactionof 9.00 g of Al with excess dilute H₂SO₄?

2 Al(s) + 3 H₂SO₄(aq) -----> 3 H₂(g) + Al₂(SO₄)₃

(A) 5.61 L
(B) 11.2 L
(C) 33.6 L
(D) 67.2 L

9. Which substance has the highest boiling point?

(A) CH₄
(B) He
(C) HF
(D) Cl₂

10. When sugar is dissolved in water, the resulting solution

(A) has a higher freezing point than pure water.
(B) has a higher boilng point than pure water.
(C) has a higher vapor pressure than pure water.
(D) has a lower osmotic pressure than pure water.

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