1. Chem 1310: Introduction to physical chemistry Part 1a: PSP chapter 6 Peter H.M. Budzelaar

2. PSP 6.1, p217 (a)One hot dog is 160 Cal. How much in joules? (b)1 Watt of power is 1 J/s; an x-Watt device running for y seconds uses x*y joules. How much electrical energy (in joules) is use by a 75-watt bulb burning for 3 hours? (c)One packet of sweetener provides 16 kJ of nutritional energy. How much is this in kcal?

3. PSP 6.2, p222 The internal energy of a mixture of hydrogen and oxygen decreases by 2400 J when it burns. The surroundings are heated by 1.89 kJ. How much work is done by the system on the surroundings?

4. PSP 6.3, p225 250 g of Al is heated using 24.1 kJ of energy. The initial temperature is 5.0°C; what is the final temperature? (specific heat of Al: 0.902 J g -1 K -1, from Table 6.1)

5. PSP 6.4, p227 A filled coffee cup (250 mL) is heated from 37°C to 65°C, no work being done. What is  E system ?

6. PSP 6.5, p228 400 g Fe is heated in a flame, then immersed in 1000g water of 20.0°C. The final temperature is 32.8°C; what was the temperature of the Fe before cooling? (specific heat of Fe: 0.451 J g -1 K -1, from Table 6.1)

7. PSP 6.6, p233 For K melting at 1 atm, the heat transfer is 14.6 cal/g. At the melting point, the densities of solid and liquid K are 0.86 and 0.82 g/ml, respectively. A volume change of 1 mL at 1 atm corresponds to 0.10 J of work. Calculate  H and  E for melting 1.00 g of K.

8. PSP 6.7, p235 Sublimation of 1 mol of iodine at 25°C and 1 bar has  H = +62.4 kJ. (a)How much energy must be transferred to vaporize 10.0 g of solid iodine. (b)How much energy is transferred if 3.42 g iodine vapour condenses to solid. (c)Is the change under (b) exothermic or endothermic?

9. PSP 6.8, p238 Ca (s) + ½ O 2 (g)  CaO (s)  H° = -635.09 kJ Write the equation and calculate the enthalpy change for forming 4 moles of O 2 (g) from CaO.

10. PSP 6.9, p240 Given the equation H 2 O (l)  H 2 (g) + ½ O 2 (g)  H° = +285.8 kJ how much thermal energy is required to maintain constant temperature when decomposing 12.6 g liquid water to H 2 and O 2 at 25°C?

11. PSP 6.10, p244 1 Fritos chip (1.0 g) is placed in a bomb calorimeter (heat capacity 877 J/K) containing 832 g of water. Burning (with excess oxygen) results in a temperature change from 20.64 to 25.43°C. Check that this agrees with the statement that the chip provides 5 Cal of energy when metabolized.

12. PSP 6.11, p245 100 mL 1M HCl and 100 mL 1M NaOH, both at 20.4°C, are combined in a coffee cup calorimeter. Given the neutralization equation H + (aq) +OH - (aq)  H 2 O (l)  H° = -58.7 kJ calculate the final temperature.

13. PSP 6.12, p248 Given the equations C (s) + O 2 (g)  CO 2 (g)  H° = -393.5 kJ CO (g) + ½ O 2 (g)  CO 2 (g)  H° = -283.0 kJ Calculate  H° for: C (s) + ½ O 2 (g)  CO (g)

14. PSP 6.13, p 249 Write thermochemical equations for: (a)Standard molar enthalpy of formation of NH 3(g) at 25°C is -46.11 kJ/mol (b)Standard molar enthalpy of formation of CO (g) at 25°C is -110.525 kJ/mol

15. PSP 6.14, p252 Nitroglycerin,  H f ° = -364 kJ/mol, decomposes explosively according to 2 C 3 H 5 (NO 3 ) 3 (l)  3 N 2 (g) + ½ O 2 (g) + 6 CO 2 (g) + 5 H 2 O (g) Calculate the energy transfer when 10.0 g nitroglycerin explodes.

16. PSP 6.15, p253 Using Table 6.2, calculate the molar heat of combustion of SO 2 (g) to SO 3 (g).

17. PSP 6.16, p258 For whole milk (5.0% carbohydrate, 4.0% fat, 3.3% protein by wt): (a) estimate the caloric value of an 8-oz (227-g) glass (b) how long would this glass support a 70-kg male taking a leisurely walk?

18. Work and Volume A volume change requires work: w = p  V when expressed in the correct units! We need both in SI units: p in Pascal: 1 atm = 101.325 kPa = 101325 kg m -1 s -2  V in m 3 : 1 L = 1 dm 3 = 10 -3 m 3 then w = p  V in (kg m -1 s -2 )(m 3 ) = kg m 2 s -2 = J

19. Review Question 33 400 g Fe is heated in a flame, then immersed in 1000g water of 20.0°C. The final temperature is 32.8°C; what was the temperature of the Fe before cooling? (specific heat of Fe: 0.451 J g -1 K -1, from Table 6.1)

20. Review Question 39 200 g Al is heated in a flame, then immersed in 500 mL water of 22.0°C. The final temperature is 33.6°C; what was the temperature of the Al before cooling? (specific heat of Al: 0.902 J g -1 K -1, from Table 6.1; density of water at 22.0°C: 0.98 g/cm 3 ) (the answer on p A.85 is wrong)

21. Review Question 40 200 g Cu is heated in a flame to 500°C, then immersed in 1000g water of 23.4°C. What is the final temperature? (specific heat of Cu: 0.385 J g -1 K -1, from Table 6.1)

22. Review Question 87 Given: PbO (s) + C (s)  Pb (s) + CO (g)  H° = 106.8 kJ(1) 2 C (s) + O 2 (g)  2 CO (g)  H° = -221.0 kJ(2) asked: Pb (s) + ½ O 2 (g)  PbO (s)  H° = ??? Endothermic or exothermic?

23. Review Question 94 6 CO 2 + 6 H 2 O  6 O 2 + C 6 H 12 O 6  H° = ??? From Table 6.2,  H f °(CO 2 (g) ) = -285.830 kJ/mol  H f °(H 2 O (l) ) = -393.509 kJ/mol  H f °(C 6 H 12 O 6 (s) ) = -1274.4 kJ/mol