Chemistry Assignment Guruh Worksheet

NI 2

ENGR 1540 Worksheet 17 Chapter 10

1. On the basis of your experience, predict which of the following reactions are spontaneous.
a. CO2(s)→CO2(g) at 25℃
b. NaCl(s)→NaCl(l) at 25℃
c. 2NaCl(s)→2Na(s)+Cl2(g)
d. CO2(g)→C(s)+O2(g)

2. Identify each of the processes listed as spontaneous or nonspontaneous.
a. A group of cheerleaders builds a human pyramid.
b. Table salt dissolves in water.
c. A cup of cold coffee in a room becomes steaming hot.
d. Water molecules in the air are converted to hydrogen and oxygen gases.
e. A person peels an orange, and you smell it from across the room.

3. Identify each of the processes listed as spontaneous or nonspontaneous.
a. Oxygen molecules dissociate to form oxygen atoms.
b. A tray of water is placed in the sum 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.

4. For each process, tell whether the entropy change of the system is positive or negative.
a. A glassblower heats glass (the system) to its softening temperature.
b. A teaspoon of sugar dissolves in a cup of coffee. (The system consists of both sugar and coffee.)
c. Calcium carbonate precipitates out of water in a cave to form stalactites and stalagmites. (Consider only the calcium carbonate to be the system.)

5. Without doing a calculation, predict whether the entropy change will be positive or negative when each of the following reactions occurs in the direction it is written.
a. CH3OH(l)+3/2O2(g)→CO2(g)+2H2O(g)
b. Br2(l)+H2(g)→2HBr(g)
c. Na(s)+1/2F2(g)→NaF(s)
d. CO2(g)+2H2(g)→CH3OH(l)
e. 2NH3(g)→N2(g)+3H2(g)

6. For the following chemical reactions, predict the sign of ΔS for the system. (Note that this should not require any detailed calculations.)
a. Fe(s)+2HCl(g)→FeCl2(s)+H2(g)
b. 3NO2(g)+H2O(l)→2HNO3(l)+NO(g)
c. 2K(s)+Cl2(g)→2KCl(s)
d. Cl2(g)+2NO(g)→2NOCl(g)
e. SiCl4(g)→Si(s)+2Cl2(g)

7. Use tabulated thermodynamic data to calculate the standard entropy change of each of the reactions listed below.
a. Fe(s)+2HCl(g)→FeCl2(s)+H2(g)
b. 3NO2(g)+H2O(l)→2HNO3(l)+NO(g)
c. 2K(s)+Cl2(g)→2KCl(s)
d. Cl2(g)+2NO(g)→2NOCl(g)
e. SiCl4(g)→Si(s)+2Cl2(g)

8. Calculate ΔG° at 45℃ for reactions for which
a. ΔH°=293 kJ; ΔS°=-695 J/K
b. ΔH°=-1137 kJ; ΔS°=0.496 J/K
c. ΔH°=-86.6 kJ; ΔS°=-382 J/K

9. Using tabulated thermodynamic data, calculate ΔG° for these reactions.
a. Fe(s)+2HCl(g)→FeCl2(s)+H2(g)
b. 3NO2(g)+H2O(l)→2HNO3(l)+NO(g)
c. 2K(s)+Cl2(g)→2KCl(s)
d. Cl2(g)+2NO(g)→2NOCl(g)
e. SiCl4(g)→Si(s)+2Cl2(g)

10. Using tabulated thermodynamic data, calculate ΔG° for these reactions.
a. Mg3N2(s)+6H2O(l)→2NH3(g)+3Mg(OH)2(s)
b. 4CH3NH2(g)+9O2(g)→4CO2(g)+10H2O(l)+2N2(g)
c. Fe3O4(s)+4CO(g)→3Fe(s)+4CO2(g)
d. P4O10(s)+6H2O(l)→4H3PO3(aq)