Ch. 5, 19, & 8.9 thermodynamics [65 points] ** test** AP Chem

For problems involving calculations, show the relevant equation (or formula, and conversion factor(s)), show your work in an organized manner, put the proper units in your calculations / answer, and have the proper number of significant figures in your answer.

1. Using thermodynamics, in regards to boiling water, determine [assume ∆H, ∆S, & ∆G are independent of temperature; 15 points]

a. the enthalpy of the process

b. the entropy of the process

c. based on the above information, determine the temperature range, where the process is spontaneous.

2. If dissolving 5**.**0 g NH_{4}NO_{3 (s)} in 50**.**0 mL water lowers the temperature of water by 3**.**0 °C, what is Δ H_{f} (NO_{3}^{ -}) ? [15 points]

3. Determine ∆S (i.e. zero, positive, negative, or ambiguous) of the following reactions; rationalize your answer (do not calculate its value). [10 points]

a. C

_{2}H_{6 (g)}+ O_{2 (g)}--> CO_{2 (g)}+ H_{2}O_{(g) }b. NaCl

_{ (aq)}+ AgNO_{3 (aq)}--> products

4. In regards to the reaction: CH_{3}Cl _{(g) }+ Cl_{2 (g)} --> HCl _{(g)} + CH_{2}Cl_{2 (g)} [15 points]

a. determine ∆H of the reaction

b. determine ∆H of the reaction: 10

.0 g CH_{3}Cl_{(g)}+ 20.0 Cl_{2 (g)}--> HCl_{(g) }+ CH_{2}Cl_{2 (g)}

**Old topics **[10 points]

5. Describe London intermolecular forces in polar and nonpolar compounds in terms of its dipole moment (define this term).