Use the information to determine the sign of ∆H° and ∆S° for the given process.   Spontaneous at all temperatures   Spontaneous at Low Temperatures   Spontaneous at High Temperatures   Never Spontaneous   1. Positive ∆H° and Positive ∆S°  2. Positive ∆H° and Negative ∆S°  3. Negative ∆H° and Positive ∆S°  4. Negative ∆H° and Negative ∆S°

Identify each of the processes listed as spontaneous or non-spontaneous. For each non spontaneous process, describe the corresponding spontaneous process in the opposite direction. (a) Oxygen molecules dissociate to form oxygen atoms. (b) A tray of water is placed in the sun on a warm day and freezes. (c) A solution of salt water forms a layer of acid on top of a layer of base. (d) Silver nitrate is added to a solution of sodium chloride and a precipitate forms. (e) Sulfuric acid sitting in a beaker turns into water by giving off gaseous SO3.

For each pair of items, tell which has the higher entropy and explain why. (a) Item 1, a sample of solid CO2 at -78°C, or item 2, CO2 vapor at 0°C (b) Item I, solid sugar, or item 2, the same sugar dissolved in a cup of tea (c) Item 1, a 100-mL sample of pure water and a 100-mL sample of pure alcohol, or item 2, the same samples of water and alcohol after they have been poured together and stirred

Human DNA contains almost twice as much information as is needed to code for all the substances produced in the body. Likewise, the digital data sent from Voyager II contained one redundant bit out of every two bits of information. The Hubble space telescope transmits three redundant bits for every bit of information. How is entropy related to the transmission of information? What do you think is accomplished by having so many redundant bits of information in both DNA and the space probes?

Indicate which substance in the given pairs has the higher entropy value. Explain your choices.. (a) C2H5OH(l) or C3H7OH(l). (b) C2H5OH(l) or C2H5OH(g). (c) 2H(g) or H(g)

10.45 Calculate G at 45°C for reactions for which (a) H = 293 kJ; S= -695 J/K (b) H= -1137 kJ; S = 0.496 kJ/K (c) H = -86.6 kJ; S = -382 J/K

What is a spontaneous process? Give three examples of spontaneous processes. Give three examples of nonspontaneous processes.

Given the values of H and S, which of the following changes will be spontaneous at constant T and p? a. H = + 25 kJ, S = + 5.0 J/K, T = 300. K b. H = + 25 kJ, S = + 100. J/K, T = 300. K c. H = 10. kJ, S = + 5.0 J/K, T= 298 K d. H = 10.kJ, S =40.J/K, T = 200.K

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?

Which substance has the higher entropy? (a) a sample of pure silicon (to be used in a computer chip) or a piece of silicon containing a trace of another element such as boron or phosphorus (b) O2(g) at 0 C or O2(g) at 50 C (c) I2(s) or I2(g), both at room temperature (d) one mole of O2(g) at 1 bar pressure or one mole of O2(g) at 0.01 bar pressure (both at 298 K)