1. Units 2 - 3 Matter, Energy, and Changes

2. Matter & Changes

3. Matter
Is anything that has mass and volume

4. Matter
States:
Gas – no definite shape or volume, particles randomly scattered (high entropy), particles moving quickly in constant motion, highly compressible, low density, rapid diffusion, high expansion on heating

5. Matter
States:
Liquid – no set shape, definite volume, particles somewhat organized, particles free to move, slightly compressible, high density, slow diffusion, low expansion on heating

6. Properties of Liquids
Viscosity – friction or resistance to motion, increases as temperature decreases
Surface tension – molecules at the surface experience imbalanced attractive forces

7. Matter
States:
Solid – has particular shape, definite volume, particles very organized and close together (low entropy), particles move only very slightly, low compressibility, high density, slow diffusion, low expansion on heating

8. Basic Types of Solids
Crystalline solids – are made of atoms arranged in highly ordered, repeated patterns called unit cells
Amorphous solids - appear solid, but are more of a super-cooled liquid, have high viscosity, gradually soften as temperature increases

9. Properties of Solids
Some solids are good conductors due to particles being in contact with each other and passing the energy from one to another

10. Matter
State of matter at room temperature depends on strength of intermolecular forces
For example, a substance with strong IM forces will be a solid while a substance with very weak IM forces will be a gas

11. Matter Intermolecular Forces
Are the forces between neighboring molecules

12. Matter Intermolecular Forces: Dispersion forces
Attraction between 2 induced dipoles

13. Matter Intermolecular Forces: Dipole-dipole forces
Attraction between 2 permanent dipoles

14. Matter Intermolecular Forces: Hydrogen “bond”:
Attraction between a partially positive H on one molecule and a partially negative atom on another molecule

15. Matter
Properties:
Physical – density, color, melting point (can be observed w/o altering substance)
Chemical – flammability, reactivity (must alter to observe)

16. Matter
Changes:
Physical – matter is not altered, particles stay in same arrangement (includes change of state)
Chemical – identity of substance is altered, particles are rearranged

17. Matter
Law of Conservation of matter: matter is neither created nor destroyed in any process

18. Elements, compounds & mixtures
Element – substance that cannot be separated into simpler substances by chemical change, organized in Periodic Table

19. Elements, compounds & mixtures
Element – substance that cannot be separated into simpler substances by chemical change, organized in Periodic Table
Compound – 2 or more elements combined by chemical change

20. Elements, compounds & mixtures
Pure Substance or Mixture
Pure Substance – has unique set of chemical & physical properties (includes all elements and compounds)

21. Elements, compounds & mixtures
Pure Substance or Mixture
Pure Substance – has unique set of chem & phys properties (includes all elements and compounds)
Mixture – blend of 2 or more substances (not combined chemically)

22. Elements, compounds & mixtures
Pure Substance or Mixture
Pure Substance – has unique set of chem & phys properties (includes all elements and compounds)
Mixture – blend of 2 or more substances (not combined chemically)
Types:
Heterogeneous – visibly different parts
Homogeneous – no visibly different parts

23. Elements, compounds & mixtures
Mixture Separation
Filtration – often used for heterogeneous mixes

24. Elements, compounds & mixtures
Mixture Separation
Filtration – often used for heterogeneous mixes (not homogeneous)
Distillation – heat liquid & drive it off, leaving solid (or liquid w/ higher boiling point)

25. Elements, compounds & mixtures
Mixture Separation
Filtration – often used for heterogeneous mixes
Distillation – heat liquid & drive it off, leaving solid (or liquid w/ higher boiling point)
Crystallization – evaporate liquid, leaving solid

26. Elements, compounds & mixtures
Mixture Separation
Filtration – often used for heterogeneous mixes
Distillation – heat liquid & drive it off, leaving solid (or liquid w/ higher boiling point)
Crystallization – evaporate liquid, leaving solid
Chromatography – flow solution along stationary source

27. Energy & Temperature

28. Energy
Energy is the capacity to do work or produce heat.

29. Energy
Forms:
Radiant
ex. sunlight

30. Energy
Forms:
Radiant – ex. sunlight
Kinetic
energy carried by objects in motion (includes mechanical & thermal)

31. Energy Forms: Potential
Radiant – ex. sunlight
Kinetic – energy carried by objects in motion (includes mechanical & thermal)
Potential
due to position/stored energy (includes electrical & chemical)

32. Energy
Measuring:
calories (cal) – amount of heat needed to raise temperature of 1 g H2O by 1 C
1 cal = 1 g × 1 C
Food energy is in Calories, 1 Cal = 1 kcal

33. Energy Measuring: SI unit is Joule (J)
calories (cal) – amount of heat needed to raise temperature of 1 g H2O by 1 C
1 cal = 1 g * 1 C
Food energy is in Calories, 1 Cal = 1 kcal
SI unit is Joule (J)

34. Energy
Measuring:
SI unit is Joule (J), 1 J is about the energy to lift a medium-sized apple 1 meter from ground
1 cal = J

35. Energy Law of Conservation of Energy:
in any process, energy is neither created nor destroyed

36. Temperature What is temperature?
comparison of how hot or cold an object is with some standard
measure of the average kinetic energy of the particles in a sample of matter

37. Temperature
Units for Temperature
Fahrenheit
Celsius
Kelvin (SI units)

38. Temperature Units for Temperature Kelvin (SI units)
Fahrenheit
Celsius
Kelvin (SI units)
Why don’t we use a degree mark with Kelvin temperatures?
What is the lowest Kelvin temperature?
Why do we call it absolute zero?

39. Temperature Units for Temperature A quick look at the three scales.
0 C = 273 K = 32 F
100 C = 373 K = 212 F

40. Temperature
Converting Fahrenheit/Celsius
C = 5/9 × (F – 32)

41. Temperature
Convert 98.6 F to C
Convert 25 C to F

42. Temperature
Converting Kelvin/Celsius
C = K – 273

43. Temperature
Convert 399 K to C
Convert 25 C to K.

44. Changes of State

45. Changes of State
Energy and change of state…
To change states, particles must overcome the attractive forces holding them together (the number of particles does not change)

46. Changes of State
Vaporization
Liquid changes to a gas, also called evaporation, requires energy input

47. Changes of State Vaporization
Liquid changes to a gas, also called evaporation, requires energy input
Rapidly moving particle near surface of liquid gains enough energy to escape attractive forces of other particles

48. Volatile liquid – one that readily evaporates
Changes of State
Vaporization
Liquid changes to a gas, also called evaporation, requires energy input
Rapidly moving particle near surface of liquid gains enough energy to escape attractive forces of other particles
Volatile liquid – one that readily evaporates

49. Changes of State
Boiling point
Temperature at which vapor pressure becomes equal to the atmospheric pressure

50. Changes of State
Heat of vaporization
Amount of heat necessary to vaporize a given amount of liquid

51. Changes of State
Heat of vaporization
You have 18.2 moles of water. How much energy is needed to vaporize the sample?
(Molar heat of vaporization for water = 40.7 kJ/mole)

52. Changes of State
Condensation
Gas changes to a liquid, releases energy

53. Changes of State
Freezing (Solidification)
Particles get closer together and more organized than in the liquid state, releases energy

54. Changes of State
Melting (Liquefying)
Particles become less organized and farther apart, requires energy input

55. Changes of State
Melting
Melting point - temperature at which solid and liquid form of substance exist in equilibrium, also called freezing point

56. Changes of State
Melting
Heat of fusion - amount of heat needed to convert a given amount of solid into a liquid

57. Changes of State
Melting
You have a 278 mole block of ice. How much energy is needed to melt it?
(Molar heat of fusion for water = 6.00 kJ/mole)

58. Changes of State
Sublimation
Solid changes directly to a gas, requires energy input

59. Changes of State
Deposition
Gas changes directly to a solid, releases energy

60. Changes of State
Heating curves
Describe changes of state of matter, plot of sample temperature as a function of time

61. Changes of State

62. Changes of State
Phase diagrams
Relates states of matter to temperature and pressure

63. Changes of State