1. 15 grams of solid NaOH was dissolved in 325 mL of water at 21 °C. [15 points]

a. what is the enthalpy of the above reaction ?

b. what is the change in the temperature of water ?

c. what is the final temperature of water ?

2. Determine ∆H for the reaction [15 points]

C₆H₄(OH)_{2 (aq)} + H₂O_{2 (aq)}  -->  C₆H₄O_{2 (aq)} + 2 H₂O _(l)

using the following information

C₆H₄(OH)_{2 (aq)} -->  C₆H₄O_{2 (aq)} + H_{2 (g)}               ∆H₁ = 177.4 kJ

H_{2 (g)} + ½ O_{2 (g)} -->  H₂O _(g)                                 ∆H₂ = - 241.8 kJ

H_{2 (g)} + O_{2 (g)} -->  H₂O_{2 (aq)}                                   ∆H₃ = - 191.2 kJ

H₂O _(g) -->  H₂O _(l)                                                ∆H₄ = - 43.8 kJ

3. 5.0 grams of benzoic acid dissolved in 100. grams of carbon tetrachloride has a boiling point of 77.5 °C. [15 points]

a. what is the molality of benzoic acid in solution ?

b. how many moles of benzoic acid was dissolved in the solution ?

c. what is the molar mass of benzoic acid ?

4. 25 mL ethylene glycol (density = 1.114 g / mL; molar mass = 62 g / mol) and 25 mL water were mixed to form a solution. [15 points]

a. what is the molarity of ethylene glycol in the solution ?

b. what is the molality of ethylene glycol in the solution ?

c. what is the mole fraction of ethylene glycol in the solution ?