Macmillan Learning AS= A heat source generates heat at a rate of 75.0 W (1 W = 1 J/s). How much entropy does this produce per hour in the surroundings at 29.2 "C? Assume the heat transfer is reversible. J K-h

Define the following: a. spontaneous process b. entropy c. positional probability d. system e. surroundings f. universe

According to Lambert, leaves lying in the yard and playing cards that are in disarray on a table have not undergone an increase in their thermodynamic entropy. Suggest another reason why leaves and playing cards may not be a good analogy for the entropy of a system containing, for example, only H2O molecules or only O2 molecules.

Through photosynthesis, plants build molecules of sugar containing several carbon atoms from carbon dioxide. In the process, entropy is decreased. The reaction of CO2with formic acid to form oxalic acid provides a simple example of a reaction in which the number of carbon atoms in a compound increases: CO2(aq)+HCOOH(aq)H2C2O4(aq) (a) Calculate the standard entropy change for this reaction and discuss the sign of S . (b) How do plants carry out reactions that increase the number of carbon atoms in a sugar, given the changes in entropy for reactions like this?

Solid NH4NO3 is placed in a beaker containing water at 25 C. When the solid has completely dissolved, the temperature of the solution is 23.5 C. (a) Was the process exothermic or endothermic? (b) Was the process spontaneous? (c) Did the entropy of the system increase? (d) Did the entropy of the universe increase?

A key component in many chemical engineering designs is the separation of mixtures of chemicals. (a) What happens to the entropy of the system when a chemical mixture is separated? (b) Are designs for chemical separation more likely to rely on spontaneous or nonspontaneous processes?

The reaction CO2(g)+H2(g)CO(g)+H2O(g) is not spontaneous at room temperature but becomes spontaneous at a much higher temperature. What can you conclude from this about the signs of H and S , assuming that the enthalpy and entropy changes are not greatly affected by the temperature change? Explain your reasoning.

Calculate the entropy change for each of these processes. thereby verifying the predictions made in Conceptual Exercise 16.4. (a) 2 CO2(g) 2 CO(g) + O2(g) (b) NaCl(s) NaCl(aq) (c) MgCO3(s) MgO(s) + CO2(g)

There is another free energy state function, the Helmholtz free energy (A), defined as A = E — TS. Comparing this to the definition of G, we see that internal energy has replaced enthalpy in the definition. Under what conditions would this free energy tell us whether or not a process is spontaneous?

10.69 If a sample of air were separated into nitrogen and oxygen molecules (ignoring other gases present), what would be the sign of for this process? Explain your answer. The next four questions relate to the following paragraph [Frank L. Lambert, Journal of Chemical Education, 76(10), 1999, 1385]. "The movement of macro objects from one location to another by an external agent involves no change in the objects' physical (thermodynamic) entropy. The agent of movement undergoes a thermodynamic entropy increase in the process."