Chapter 5 - Summary Quiz

Your name:

Required

1. Explain what is wrong with this thinking.  "For the reaction:

2Mg(s) + O2 (g) rightarrow.gif (847 bytes) MgO (s)  delta.gif (63 bytes)G = -1139 kJ

This reaction has a very negative delta.gif (63 bytes)G, so it will react spontaneously, and very rapidly at room temperature."

2. Does the entropy of the system increase when the temperature rises?
a) yes, Ssystem increases as the temperature increases.
b) no, Ssystem decreases as the temperature increases.
c) Ssystem will be unaffected by a temperature increase.

3. The entropy of the universe always increases, whenever any change occurs.
True     False

4. Using a table of thermodynamic values, calculate the standard entropy change for this reaction:

N2O4 (g) 2NO2 (g)

Sreaction =  J/K

5. Using a table of thermodynamic values, calculate the standard free energy for this reaction at 25 oC:

N2O4 (g) 2NO2 (g)

G =  kJ

6. Is the reaction described in question 5 at equilibrium when the pressure of NO and N2O4 = 1 bar, and the temperature is 25 oC?
Yes      No