1. ΔH ΔS
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Calculations
spontaneity
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500 1 1

2. Law that states that energy cannot be created or destroyed2 2

3. Law of conservation of Energy3 3

4. ΔH is the change in _________ during a process4 4

5. enthalpy 5 5

6. Sign of ΔH for boiling water6 6

7. positive 7 7

8. Determine the sign of ΔH and ΔS for: Mg3N2(s)  3 Mg(s) + N2(g) + 200kJ8 8

9. ΔH = negative
ΔS = positive . 9 9

10. In an endothermic reaction, the standard enthalpy of formation of the products is ____________ (greater than or less than) the standard enthalpy of formation of the reactants? 10 10

11. greater than 11 11

12. Entropy is: 12 12

13. A measure of disorder of a system13 13

14. Arrange the following in order of increasing entropy:
HCl(g), HCl(aq), HCl(s), HCl(l) 14 14

15. HCl(s), HCl(l), HCl(aq), HCl(g)15 15

16. What is the sign of ΔS for the sublimation of carbon dioxide.16 16

17. positive 17 17

18. Predict the sign of ΔS for the reaction below:
CaCO3  CaO + CO2 18 18

19. positive 19 19

20. When ammonium chloride dissolves in water, the temperature of the water drops. What is the sign of ΔS? 20 20

21. positive 21 21

22. Is the reaction spontaneous at this temperature?
For a reaction,
ΔS = 64.0 J/K
ΔH = 320. kJ/mol
Find ΔG at 298K
Is the reaction spontaneous at this temperature?

23. 301 kJ, no 23 23

24. Under what conditions will this reaction become spontaneous?
For a reaction,
ΔS = 64.0 J/K
ΔH = 320. kJ/mol
Under what conditions will this reaction become spontaneous? 24 24

25. Above 5.00 x 103 K 25 25

26. Under what conditions will this reaction become spontaneous?
For a reaction,
ΔS = J/K
ΔH = kJ/mol
Under what conditions will this reaction become spontaneous? 26 26

27. Below K

28. Use the bond energy table to find the energy change for breaking the reactant bonds in the reaction:
2Cl2 + O2  2Cl2O
BOND ENERGY
Cl-Cl
242 kJ/mol
O=O
495 kJ/mol
Cl-O
203 kJ/mol 28 28

29. 979kJ 29 29

30. Use the bond energy table to find the energy change for creating the product bonds in the reaction:
2Cl2 + O2  2Cl2O
BOND ENERGY
Cl-Cl
242 kJ/mol
O=O
495 kJ/mol
Cl-O
203 kJ/mol 30 30

31. -812kJ 31 31

32. Find ΔG, ΔH and ΔS for the reaction:
2Fe + 3Cl2  2FeCl3
ΔH°f
(kJ/mol)
ΔG°f
S°f
(J/mol K) Fe --
Cl2
223
FeCl3
-399
-334 32 32

33. ΔG = -668 kJ ΔH = -798kJ ΔS = 436 J/K 2Fe + 3Cl2  2FeCl3 ΔH°f
(kJ/mol)
ΔG°f
S°f
(J/mol K) Fe --
Cl2
223
FeCl3
-399
-334 33 33

34. What are the signs of ΔG, ΔH and ΔS for a reaction that is spontaneous at any temperature?34 34

35. ΔG = negative
ΔH = negative
ΔS = positive 35 35

36. What are the signs of ΔG, ΔH and ΔS for melting wax36 36

37. ΔG = negative
ΔH = positive
ΔS = positive 37 37

38. For a certain reaction: ΔH = 375. kJ ΔS = -125 J/K
At what temperature will this reaction become spontaneous? 38 38

39. The reaction is never spontaneous39 39

40. Determine the signs of ΔG, ΔH and ΔS for this process.
A student forms a yellow precipitate by mixing aqueous solutions of lead(II) nitrate and potassium iodide.
Pb I-  PbI2
Determine the signs of ΔG, ΔH and ΔS for this process. 40 40

41. ΔG = negative
ΔH = negative
ΔS = negative 41 41

42. Determine the signs of ΔG, ΔH and ΔS for this process.
When baking soda and vinegar are mixed in a beaker, the beaker feels cold to the touch.
Determine the signs of ΔG, ΔH
and ΔS for this process. 42 42

43. ΔG = negative
ΔH = positive
ΔS = positive 43 43

44. Name the law that says that in a natural process the entropy increases

45. The Second Law of Thermodynamics

46. What are the signs of ΔH, ΔG and ΔS for the condensation of a vapor?

47. ΔG = negative
ΔH = negative
ΔS = negative 47 47

48. Write the thermochemical equation for the formation of methane gas (CH4).
ΔHf°= -75kJ/mol

49. C H2  CH kJ

50. At what temperature will the process below be spontaneous:
H2O(l)  H2O(v)

51. 100°C

52. Iron rusts when it reacts with oxygen in the air in the presence of water. Determine the signs of ΔG, ΔH and ΔS for iron rusting.

53. ΔG = negative
ΔH = negative
ΔS = negative 53 53