Ch. 10, 14, & 19 thermodynamics & nuclear chem test [80 points] Chemistry

Show your work in an organized manner, includes any relevant equation / formula, proper units in your work / answer, and the proper number of significant figures in your answer.

 

1. How much heat is needed to change ice at – 5 °C to liquid water at 25 °C ? The specific heat of ice is 2.09 J / g K. [15 points]

 

2. What is ∆ S reaction ? Justify your answer. [10 points]

a. AgNO 3 (aq) + CaCl 2 (aq)--> AgCl (s) + Ca(NO 3) 2 (aq)

b. NO (g) + O 2 (g) --> NO 2 (g) + O 3 (g)

3. NaOH (s)  -->  Na +(aq) + OH -(aq)                ∆H = - 44 kJ [15 points]

a. how much heat is given-off or consumed in the above reaction, when 2.0 g solid NaOH was dissolved in water ?

b. if 2.0 g solid NaOH was dissolved in 45 g water at 25 °C, what would be the temperature when all of the NaOH was dissolved ?

 

4. write the nuclear reaction described below: [20 points]

a. 95Kr undergoes beta minus decay: _______________________

b. 80Rb undergoes beta plus decay: ________________________

c. 187Hg undergoes alpha decay: ________________________

d.

e. 4He + 11B -->  __________

5. What does the equation: E = mc 2 mean ? [10 points]

 

6. The half-life of 35S is 87 days. How much time would it take for 200.0 g 35S to decay to 25.0 g 35S ? [10 points]