Question

1. Manufacturers of headache remedies routinely claim that their own brands are more potent pain relievers than the competing brands. Their way of making the comparison is to compare the number of molecules in the standard dosage. Tylenol uses 325 mg of acetaminophen (C₈H₉NO₂) as the standard dose, while Advil uses 2.00 x 10² mg of ibuprofen (C₁₃H₁₈O₂). Find the number of molecules of pain reliever in the standard doses of (a) Tylenol and (b) Advil.

2. The drawing shows an ideal gas confined to a cylinder by a massless piston that is attached to an ideal spring. Outside the cylinder is a vacuum. The cross-sectional area of the piston is A = 2.50 × 10^-3 m². The initial pressure, volume, and temperature of the gas are, respectively, P₀, V₀ = 6.00 × 10^-4 m³ and T₀ = 273 K, and the spring is initially stretched by an amount x₀ = 0.092 m with respect to its unstrained length. The gas is heated, so that its final pressure, volume, and temperature are P_f, V_f and T_f and the spring is stretched by an amount x_f = 0.13 m with respect to its unstrained length. What is the final temperature of the gas?

Piston

3. A container holds 1.2 mol of gas. The total average kinetic energy of the gas molecules in the container is equal to the kinetic energy of a 8.4x10^-3 kg bullet with a speed of 620 m/s. What is the Kelvin temperature of the gas?

4. Carbon tetrachloride (CCl₄) is diffusing through benzene (C₆H₆), as the drawing illustrates. The concentration of CCl₄ at the left end of the tube is maintained at 1.40 x 10^-2 kg/m³, and the diffusion constant is 18.2 x 10^-10 m²/s. The CCl₄ enters the tube at a mass rate of 5.13 x 10^-13 kg/s. Using these data and those shown in the drawing, find (a) the mass of CCl₄ per second that passes point A and (b) the concentration of CCl₄ at point A.

Answer 1

n = NA It No. of molecules in Tylend :- Can wete (isi 0.325g 151-2g/mol. ~ 1-3x1021 molecules. 116-023X1023) No. of molecules in Advil:- m mol-wt) 3 ( ma +) NA = 20ox 10 J (6.023 (206-3 g/mol (6.023x1043) u 5.84x1020 molecules.