Understanding Phase Changes: From Solids to Liquids and Beyond

1. Review: LIQUIDS & PHASE CHANGES

2. solid to liquid • Melting

3. What phase of matter is “B”? Pressure  A B C Temperature  Liquid

4. What can cause a phase change of matter? • Very LOW temperatures • Very HIGH pressures

5. ________is the gas phase of a substance normally solid or liquid at room temperature • Vapor

6. Freezing occurs by the release of _____ • energy

7. Describe a volatile liquid in terms of its rate of evaporation. • Evaporates quickly

8. ______ is the resistance of a liquid to flow • Viscosity

9. What phase of matter is “A”? A Pressure  B C Temperature  Solid

10. What is the normal boiling point of water? • 100C

11. Melting occurs by energy being ______. • absorbed

12. ____________ is the temperature and pressure at which all 3 states of matter are at equilibrium • Triple point

13. _______shows how states of matter are affected by changes in temperature/pressure • Phase diagram

14. solid to gas • Sublimation

15. The triple point of this substance occurs at: • 5.2 atm & 216.6 K

16. __________ is a dynamic condition in which two opposing physical or chemical changes occur at equal rates in a given closed system • Equilibrium

17. C(s) + H2O(g) CO(g) + H2(g) If the concentration of CO was increased, the system would shift to the ________ • LEFT

18. ________ is the temperature at which equilibrium vapor pressure equals atmospheric pressure • Boiling point

19. _______ is the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature. • Equilibrium vapor pressure

20. ____________ is the spontaneous mixing of two or more substances. • Diffusion

21. When energy is added to a substance, the particles would move ___________ • Faster

22. When does a liquid boil? • Equilibrium vapor pressure EQUALS atmospheric pressure

23. When energy is taken away from a substance, the particles would move __________ • Slower

24. What is the most abundant liquid? • Water

25. _____________ is a force common to all liquids that tends to pull adjacent parts of a liquid’s surface together. • Surface tension

26. List 2 examples of surface tension. • Meniscus • Droplets can form • Objects float • Capillary rise

27. List a volatile substance • Rubbing alcohol • Nail polish remover • Gasoline • hairspray

28. When a system at equilibrium is disturbed by application of a stress, it attains a new equilibrium position that minimizes the stress. This is known as ___________ • Le Chatelier’s Principle

29. liquid to solid • Freezing

30. C(s) + H2O(g) CO(g) + H2(g) If the concentration of H2O was increased, the system would shift to the ________ • Right

31. How does a substance evaporate, if equilibrium vapor pressure is LOW? WHY? • SLOWLY! • B/c there are STRONG IM forces and requires MORE kinetic energy to become a vapor

32. Describe a liquid in terms of particle spacing. • Particles are packed relatively closely together

33. Describe a liquid in terms of particle motion. • Particles vibrate around MOVING points

34. gas to liquid • Condensation

35. Describe the general volume of a liquid and use KMT to explain. • Definite VOLUME- b/c particles are close together

36. Describe the general shape of a liquid and use KMT to explain. • NO Definite SHAPE- b/c particles vibrate around moving points

37. Describe a liquid-vapor system at equilibrium. • The number of particles leaving the liquid (vaporization) EQUAL the number of particles re-entering the liquid (condensation)

38. gas to solid • Deposition

39. What happens to the boiling point of liquids on top of Mt. Everest? WHY? • Boiling point is lower • B/c atmospheric pressure is lower

40. liquid to gas • Vaporization

41. Condensation occurs when energy is (absorbed OR released). RELEASED

42. What phase of matter is “C”? A Pressure  B C Temperature  Gas

43. What is the difference between the IM forces during melting and freezing? • Melting = Less IM forces b/c more particle collisions • Freezing = MORE IM forces b/c particles are moving slower

44. Using KMT, explain the evaporation rate of a volatile liquid. • Has weak IM forces between particles so it requires LESS kinetic energy to become a vapor

45. Using KMT, explain the evaporation rate of a nonvolatile liquid. • Has strong IM forces between particles so it requires MORE kinetic energy to become a vapor

46. Arrange the following in order of increasing viscosity at room temperature: tree sap, water, salad oil. • Water, Salad Oil, Tree Sap

47. Deposition occurs when energy is (absorbed OR released). • Absorbed

48. How are boiling and evaporation alike? • Both have particles changing from a liquid to a gas

49. C(s) + H2O(g) CO(g) + H2(g) If the concentration of H2 was decreased, the system would shift to the ________ • RIGHT

50. How are boiling and evaporation different? • Evaporation ONLY takes place at the surface • Heat is needed for boiling to occur and not for evaporation