1. Figure: 05-02
Title:
Potential energy and kinetic energy.
Caption:
(a) A bicycle at the top of a hill has a high potential energy relative to the bottom of the hill. (b) As the bicycle proceeds down the hill, the potential energy is converted into kinetic energy.

2. Figure: 05-03
Title:
A closed system and its surroundings.
Caption:
Hydrogen and oxygen gases are confined in a cylinder with a movable piston. If we are interested only in the properties of these gases, the gases are the system and the cylinder and piston are part of the surroundings. Because the system can exchange energy (in the form of heat and work) but not matter with its surroundings, it is a closed system.

3. Figure: 05-04
Title:
A ball of clay can be used to show energy interconversions.
Caption:
(a) At the top of the wall, the ball has potential energy that is due to gravity. (b) As the ball falls, its potential energy is converted to kinetic energy. (c) When the ball strikes the ground, some of the kinetic energy is used to do work in squashing the ball; the rest is released as heat.

4. Figure: 05-05
Title:
Changes in internal energy.
Caption:
(a) When a system loses energy, that energy is released to the surroundings. The loss of energy is represented by an arrow that points downward between the initial and final states of the system. In this case, the energy change of the system, E = Efinal – Einitial, is negative. (b) When a system gains energy, that energy is gained from the surroundings. In this case, the gain of energy is represented by an arrow that points upward between the initial and final states of the system, and the energy change of the system is positive. Notice in both (a) and (b) that the vertical arrow originates at the initial state and has its head at the final state.

5. Figure: 05-06
Title:
Energy diagram for the interconversion of H2(g), O2(g), and H2O(l).
Caption:
A system composed of H2(g) and O2(g) has a greater internal energy than one composed of H2O(l). The system loses energy (E < 0) when H2 and O2 are converted to H2O. It gains energy (E > 0) when H2O is decomposed into H2 and O2.

6. Figure: 05-07
Title:
Sign conventions for heat and work.
Caption:
Heat, q, absorbed by the system and work, w, done on the system are both positive quantities. Both serve to increase the internal energy, E, of the system: E = q + w.

7. Figure: 05-09
Title:
Internal energy, E, a state function.
Caption:
E depends only on the present state of the system and not on the path by which it arrived at that state. The internal energy of 50 g of water at 25ºC is the same whether the water is cooled from a higher temperature to 25ºC or is obtained by melting 50 g of ice and then warming it to 25ºC.

8. Figure: 05-10
Title:
Internal energy is a state function, but heat and work are not.
Caption:
The amounts of heat and work transferred between the system and the surroundings depend on the way in which the system goes from one state to another. (a) A battery shorted out by a wire loses energy to the surroundings only as heat; no work is performed. (b) A battery discharged through a motor loses energy as work (to make the fan turn) and also loses energy as heat. Now, however, the amount of heat lost is much less than in (a). The value of E is the same for both processes, but the values of q and w in (a) are different from the values of q and w in (b).

9. Figure: 05-11
Title:
A system that does work on its surroundings.
Caption:
(a) An apparatus for studying the reaction of zinc metal with hydrochloric acid at constant pressure. The piston is free to move up and down in its cylinder to maintain a constant pressure equal to atmospheric pressure inside the apparatus. Notice the pellets of zinc in the L-shaped arm on the left. When this arm is rotated, the pellets will fall into the main container and the reaction will begin. (b) When zinc is added to the acid solution, hydrogen gas is evolved. The hydrogen gas does work on the surroundings, raising the piston against atmospheric pressure to maintain constant pressure inside the reaction vessel.

10. Figure: 05-12
Title:
Endothermic and exothermic processes.
Caption:
(a) If the system absorbs heat (endothermic process), H will be positive (H > 0). (b) If the system loses heat (exothermic process), H will be negative (H < 0).

11. Figure: 05-13
Title:
Pressure-volume work.
Caption:
A piston moving upward, expanding the volume of the system against an external pressure, P, does work on the surroundings. The amount of work done on the system by the surroundings is w = –PV.

12. Figure: 05-14
Title:
Exothermic reaction of hydrogen with oxygen.
Caption:
(a) A candle is held near a balloon filled with hydrogen gas and oxygen gas. (b) The H2(g) ignites, reacting with O2(g) to form H2O(g). The resultant explosion produces the yellow ball of flame. The system gives off heat to its surroundings. (c) The enthalpy diagram for this reaction, showing its exothermic character.

13. Figure: 05-16
Title:
H for a reverse reaction.
Caption:
Reversing a reaction changes the sign, but not the magnitude of the enthalpy change: H2 = –H1.

14. Figure: 05-17
Title:
Specific heat of water.
Caption:
Specific heat indicates the amount of heat that must be added to one gram of substance to raise its temperature by 1 K (or 1ºC). Specific heats can vary slightly with temperature, so for precise measurements the temperature is specified. The specific heat of H2O(l) at 14.5ºC is J/g-K; the addition of J of heat to 1 g of liquid water at this temperature raises the temperature to 15.5ºC. This amount of energy defines the calorie: 1 cal = J.

15. Figure: 05-18
Title:
Coffee-cup calorimeter.
Caption:
This simple apparatus is used to measure heat accompanying reactions at constant pressure.

16. Figure: 05-19
Title:
Bomb calorimeter.
Caption:
This device is used to measure heat accompanying combustion reactions at constant volume.

17. Figure: 05-21
Title:
An enthalpy diagram illustrating Hess’s law.
Caption:
The quantity of heat generated by combustion of 1 mol CH4 is independent of whether the reaction takes place in one or more steps: H1 = H2 + H3.

18. Figure: 05-22
Title:
An enthalpy diagram relating the enthalpy change for a reaction to enthalpies of formation.
Caption:
Enthalpy diagram for the combustion of 1 mol of propane gas, C3H8(g). The overall reaction is C3H8(g) + 5 O2(g)  3 CO2(g) + 4 H2O(l). We can imagine this reaction as occurring in three steps. First, C3H8(g) is decomposed to its elements, so H1 = H ºf [C3H8(g)]. Second, 3 mol CO2(g) are formed, so H2 = 3H ºf [CO2(g)]. Finally, 4 mol H2O(l) are formed, so H3 = 4H ºf [H2O(l)]. Hess’s law tells us that H ºrxn = H1 + H2 + H3. This same result is given by Equation 5.30 because H ºf [O2(g] = 0.

19. Figure: 05-24
Title:
Sources of energy consumed in the United States.
Caption:
In 2002 the United States consumed a total of 1.0 x 1017 kJ of energy.

20. Figure: UNE05.02
Title:
Exercise 5.2
Caption:
Energy diagram.

21. Figure: UNE05.03
Title:
Exercise 5.3
Caption:
Changes in a system.

22. Figure: UNE05.05
Title:
Exercise 5.5
Caption:
Reaction at constant temperature and pressure.

23. Figure: UNE05.06
Title:
Exercise 5.6
Caption:
Container in a tub of water.

24. Figure: UNE05.07
Title:
Exercise 5.7
Caption:
Gas-phase reaction.

25. Figure: UNE05.08
Title:
Exercise 5.8
Caption:
Enthalpy diagram.

26. Figure: UNE05.18
Title:
Exercise 5.18
Caption:
Solution in an apparatus.

27. Figure: UNE05.27
Title:
Exercise 5.27
Caption:
Gas in a cylinder.

28. Figure: UNE05.28
Title:
Exercise 5.28
Caption:
Oppositely charged spheres hanging by strings.

29. Figure: UNE05.92
Title:
Exercise 5.92
Caption:
Gas in a cylinder-and-piston arrangement.

30. Figure: 05-T01
Title:
Table 5.1
Caption:
Sign Conventions for q, w, and DE

31. Figure: 05-T02
Title:
Table 5.2
Caption:
Specific Heats of Some Substances at 298 K

32. Figure: 05-T03
Title:
Table 5.3
Caption:
Standard Enthalpies of Formation, DHºf, at 298 K

33. Figure: 05-T04
Title:
Table 5.4
Caption:
Compositions and Fuel Values of Some Common Foods

34. Figure: 05-T05
Title:
Table 5.5
Caption:
Fuel Values and Compositions of Some Common Fuels