Answer to Question #74327 in Physical Chemistry for Beth

Question

1. Equation VI-14a and VI-14b

(∆H│∆E)=-C(S)(T_1-T_0 ) 14a (∆H) and 14b (∆E)

Assume that the heat capacity of the calorimeter is much greater than the heat capacities of the product gases. Assuming C(S)=10.5 kJ/K determine the error in this assumption for the calculated energy of combustion of 1.0 g of benzoic acid using equation VI-12a and VI-12b

∆H= -C_p (C+D+S)( T_1-T_0 ) (12a)

∆E= -C_v (C+D+S)( T_1-T_0 ) (12b)

2. A student carries out the partial molar volume experiment using NaCl dissolved in water. His plot of ϕ vs. √m yield 2.9 as the slope and 16.3 as the y-intercept. Using a spreadsheet plot V1, V2, and V as a function of m for 0 ≤ m ≤ 3 molal. (b) At what value does V1= V2 ? (c) Give a physical interpretation for the behavior of V1, V2 and V as a function of m. (d) What is the change in total volume between 0 and 3 molal?