Ch. 8.9, 11.4, 5, 19  thermodynamics                                             55 points                                               AP chemistry

In problems involving any calculation, show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) have the proper number of significant figures in your answer.

1. What is  based on the following hypothetical experimental observation:  If 4.25 grams of solid ammonium nitrate is dissolved in 60.0 g of water at 22.0 ºC, the temperature of the water changes to 16.9 ºC.    [15 points;  source:  http://webpages.sou.edu/~chapman/ch202/Ch5/5_56.html]

2. What is the change in enthalpy in the reaction:  5.0 grams of gaseous ethanol (i.e. ethyl group containing alcohol) + 10.0 grams of oxygen gas to form carbon dioxide gas and water vapor ?  [20 points]

3. If regards to dissolving solid ammonium nitrate in water, which is an endothermic reaction,  [10 points] 

a.  Is the change in entropy positive or negative (note: ambiguous is not a choice) ?  justify / rationalize your answer.

b. The preceding reaction maybe viewed as the sum solid ammonium nitrate becoming aqueous ammonium nitrate and the formation of a hydration shell.  What is the relative magnitude of the preceding two steps in the reaction ?  justify / rationalize your answer.

4.  Is (liquid) hydrogen peroxide stable ?  That is, is the decomposition of hydrogen peroxide to form water and oxygen gas a spontaneous reaction ?  justify / rationalize your answer using principles involving thermodynamics.  [10 points]