18.Which arrow represents ?
(A) arrow (a)
(B) arrow (b)
(C) arrow (c)
(D) arrow (d)

14.A solution is prepared by dissolving 20.0 g of sucrose, in 250. g of water at 25°C. What is the vapor pressure of the solution if the vapor pressure of water at 25°C is 23.76 mm Hg? (A) 0.198 mm Hg (B) 20.5 mm Hg (C) 23.7 mm Hg (D) 24.0 mm Hg

15.Assuming that sea water is a 3.5 wt % solution of NaCl in water, calculate its osmotic pressure at 20°C. The density of a 3.5% NaCl solution at 20°C is 1.023 g/mL. (A) 1.0 atm (B) 15 atm (C) 29 atm (D) 100 atm

16.A solution of a nonelectrolyte solution contains 30.0 g of solute dissolved in 250.0g of water. The freezing point of the water is observed to be -2.50°C. The Kf for water is 1.86 °C/m and normal freezing point of water is 0.00'C. What is the molar mass of the substance? (A) 335 g/mol (B) 89.5 g/mol (C) 895 g/mol (D) 33.5 g/mol

17.Which arrow represents ? (A) arrow (a) (B) arrow (b) (C) arrow (c) (D) arrow (d)

19. The following diagram shows a close-up view of the vapor pressure curves for a pure solvent and a solution containing a nonvolatile solute dissolved in this solvent. Which curve is the solvent and what happens to the vapor pressure when the solute is dissolved in the solvent? (A) Curve (a) is the solvent and the vapor pressure decreases. (B) Curve (a) is the solvent and the vapor pressure increases. (C) Curve (b) is the solvent and the vapor pressure decreases. (D) Curve (b) is the solvent and the vapor pressure increases.

20. What is the mole fraction of oxygen in a gas mixture that is 27% oxygen and 73% nitrogen by volume? (A) 0.24 (B)0.27 (C) 0.32 (D)0.37

21.A concentration-time study of the gas phase reaction 2 A3 - 3 A2 produced the data in the table below. What is the concentration of A2 after 30 seconds? (A) 5.00 x 10*M (B) 5.25 x 10*M (C) 5.50 x 10*M (D) 6.00 x 10*M

22.The following set of data was obtained by the method of initial rates for the reaction:(A)(B)(C) (D)

23.Shown is a concentration versus time plot for a reaction involving gases A, B, and C.Which equation best represents the reaction? (A) 4A(g) - B(g) +2C(g) (B) 4A(g) +B(g) -2C(g) (C) 2C(g) →4A(g)+B(g) (D) 2C(g) +B(g)→4A(g)

24.Consider a reaction that occurs by the following one-step mechanism: A2+ B2→ 2 AB The potential energy profile for this reaction is shown below. What is the species present at reaction stage 1? (A) an intermediate (B) a product (C) a reactant (D) a transition state