Ch. 10 thermodynamics                       test       [55 points]

 

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

 

Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.

 

                                                                                                Signature:  ___________________

1. What is ΔS in the below situations (i.e. ΔS > 0; ΔS < 0; ΔS 0; ambiguous); justify / rationalize your response.  [15 points]

          a. Mix aqueous solutions of silver nitrate and sodium chloride

 b.  Dissolve magnesium chloride in water

 

 c.  Melting of ice

 

 2.  Referring to the change in Gibbs’ free energy, justify / rationalize that the melting of ice depends on temperature; include a description of this temperature dependence.  [10 points]


 3.  What is the change in temperature due to the addition of 1.5 grams of potassium hydroxide in 75 mL of water ?  [15 points]

 4. How much heat is needed to change 10.0 grams of water at 0 °C to water at 75 °C ?  [15 points]