.Name______________________________________________period_______ Unit 10: solids and liquids
760 torr (mmHg) = 1 atm = 101.3 kPa
1. Convert the following
a. 35 °C to Kelvin
308 K
d. 1.8 atm to kPa
180 kPa
b. 725 torr to atm
0.954 atm
e. 96.1 kPa to mmHg
721 mmHg
c. -10 °C to Kelvin
263 K
f. 540 torr
540 mmHg
2. How do gases compare with liquids and solids in terms of distance between their molecules?
Gas molecules are farther apart
3. Which of the following gases would have the greatest kinetic energy, He at 20 °C or He at 50 °C?
50 C
4. Which of the following gases would have the greatest velocity, He at 20 °C or Cl 2 at 20°C
He
5. Which of the following gases would have the greatest kinetic energy, O 2 at 30 °C or F 2 at 30 °C?
They have the same kinetic energy
6. Which of the following gases would effuse the fastest, fluorine or nitrogen?
nitrogen
7. Which of the following would have the highest surface tension, H 2 S (polar) or H 2 O (polar) and why?
Water, because the hydrogen bonding is stronger than dipole-dipole, so the pull inward is greater
8. Which liquid would be the most volatile, CH 4 (nonpolar) or H 2 S (polar) and why?
CH 4 , because London dispersion forces are easier to break than dipole-dipole
9. What is sublimation? Is it endothermic or exothermic?
Solid to gas, endothermic
10. Is melting endothermic or exothermic?
endothermic
11. Is condensation endothermic or exothermic?
exothermic
12. Label each of the following as exothermic or endothermic and tell if the temperature would increase or decrease when
the reaction occurs.
a. PCl 5 + 40.1kJ ↔ PCl 3 + Cl 2 endothermic, decrease temp.
b. 2H 2 + O 2  2 H 2 O ∆H = 483.6 kJ endothermic, decrease temp.
c. 2NO  N 2 + O 2
∆H = -90.29 kJ exothermic, increase temp.
d. 2NO 2 ↔ N 2 O 4 + 234kJ
exothermic, increase temp.
13. Hydrochloric acid at 20 °C is added to sodium hydroxide. The temperature after the two reactants are mixed is 34 °C.
Write a balanced reaction that shows these two being mixed (include energy in the reaction). Is this reaction endothermic
or exothermic? HCl + NaOH  NaCl + H 2 O + heat; exothermic
14. Which will have the greatest heat of vaporization? C 3 H 8 (nonpolar) or H 2 0 (polar)
Use the following substances for questions 15-17. CH 4 (nonpolar)
HCl (Polar)
15. Which is the most volatile? CH 4
16. Which has the highest surface tension? HF
17. Which has the highest heat of fusion? HF
18. What happens to the kinetic energy while a substance is boiling? Stays the same
19. What happens to the potential energy while a substance is boiling? increases
H2O
HF (polar)
20. kinetic energy stays the same
21. increase
22. boiling or vaporization
23. condensation
24. 0 ⁰C
25. 100 ⁰C
26. c
27. a
28. a
29. endothermic
30. 1
31. 1,3,5
32. 2,4
33. 5
34. 1
35. 5
Review:
36. a. Write a balanced reaction when silver phosphate reacts with potassium hydroxide
Ag 3 PO 4 + 3KOH  3AgOH + K 3 PO 4
b. How many moles of each product are formed if 3.8 moles of potassium hydroxide react?
3.8 mol silver hydroxide
1.3 mol potassium phosphate
37. What type of intermolecular forces does each of the following have?
a. CH 4
b. NH 3
c. H 2 O
d. H 2 S
London dispersion
London dispersion and hydrogen bonding London and hydrogen London and dipole-dipole
38. Which of the following molecules in #37 would have the lowest boiling point?
CH 4
39. a. Cl 2 + BaI 2  BaCl 2 + I 2
b. chlorine