1. Chapter 2
Matter and Change

2. What is Matter? Matter is anything that takes up space and has mass.
Mass is the amount of matter in an object

3. Types of Matter Pure Substance- a particular kind of matter – pure
- Elements
- Compounds
Mixture- more than one kind of matter, not chemically combined

5. What are Pure Substances?
Substances which have a single composition throughout. These can be elements or compounds

6. Pure copper Sugar Tea (water, oil)
(Cu) (C6H12O6) (Sugar, Water, tea)

7. Elements: Simplest form of matter
Atoms: Smallest part of an element
Periodic Table of Elements

8. Examples of Elements:
Anything on here!
Oxygen Gold Sodium Copper Calcium Silver
Carbon Potassium Aluminum

9. Pure Substances Cont.
Compounds: Two or more elements chemically combined
Molecule: Smallest part of a compound
A happy water molecule (H2O)

10. Sugar: a compound that has these three things chemically combined…
1. Carbon
2. Hydrogen
3. Oxygen
A Sugar Molecule
(C6H12O6 )

11. More examples of compounds:
Salt (NaCl)
Sodium
Chlorine
2. Water (H2O)
a. Hydrogen (2 atoms)
b. Oxygen
3. Baking Soda (NaHCO3)
a. Sodium
b. Hydrogen
c. Carbon
d. Oxygen (3 atoms)

12. Lets Look at Salt (NaCl)
Salt is a compound: meaning it has two or more elements chemically combined
These two elements by themselves are VERY different
The two elements?
Sodium (Na)
Chlorine (Cl)

13. Sodium (Na) Incredibly reactive, will explode in water
(And yes, we are throwing this in water one day)
Is a soft metal (you can cut it with a blunt knife)

14. Chlorine (Cl) A toxic, green gas
Used to clean swimming pools (when combined with other stuff)
The reason we almost didn’t have school that one day
Poisonous!
Dangerous!

15. Wait… So if we combine an element that EXPLODES IN WATER with…
An element that COULD KILL US…
We get…

16. The Compound Salt!!! (NaCl)
The stuff we eat EVERY day…

17. Pause for a visual… https://www.youtube.com/watch?v=n2qbtvpedMU =

18. A molecule is the smallest particle of a compound that acts as a unit
A molecule is the smallest particle of a compound that acts as a unit. Water molecule. Molecules are made of a fixed ratio of atoms.

19. What is a chemical formula?
A chemical formula tells the kind and number of atoms in a molecule.
The formula uses the symbols of the element to identify the elements present and subscripts (lowered numbers beside the symbol) to indicate how many atoms are present.

20. Mixtures

21. Compound or Mixture Compound Mixture One kind of piece- Molecules
More than one kind -
Molecule or atoms
Making is a
chemical change
Making is a
physical change
Only one kind
Variable composition

22. Which is it?
Compound
Mixture
Element

23. Properties Words that describe matter (adjectives)
Physical Properties- a property that can be observed and measured without changing the substance.
Chemical Properties- a property that can only be observed by changing the type of substance.
Both physical and chemical properties can be used to help identify a substance

24. Physical Properties
Color
Melting
Boiling

25. Chemical Properties
Flammability
Radioactivity
Reactivity

26. Properties Words that describe matter (adjectives)
Extensive Properties- only depends on the amount of matter
Intensive Properties- only depends on the type of matter, not the amount
Both intensive and extensive properties can be used to help identify a substance

27. Extensive Properties
Volume
Mass

28. Intensive Properties
Density
Luster
Color

29. States of matter
Solid- matter that can not flow and has definite volume.
Liquid- definite volume but takes the shape of its container (flows).
Gas- a substance without definite volume or shape and can flow
Plasma
high temperature low pressure
electrons separate from nucleus
Most common in the universe

30. States of Matter Definite Volume? Definite Shape? Temp. increase
Com-pressible?
Small Expans.
Solid
YES
YES NO
Small Expans.
Liquid NO NO
YES
Large Expans.
Gas NO NO
YES

31. States of Matter
Moderate Kinetic Energy - molecules move around more than in solids
Low Kinetic Energy - molecules barely move
High Kinetic Energy – molecules in rapid, constant motion

32. Condense
Freeze
Melt
Evaporate
Solid
Liquid
Gas

33. Another Way to Change States
Pressure
For some substances it will turn solids to liquids
For others it will turn liquids to solids
Silly putty
Will turn gas to liquid-
Compressor in refrigerator and AC

34. Physical Changes
A change that changes appearances, without changing the composition.
Examples?
Chemical changes - a change where a new form of matter is formed.
Also called chemical reaction.
Not phase changes
Ice is still water.

35. Mixtures Made up of two substances. Variable composition.
Heterogeneous- mixture is not the same from place to place.
Chocolate chip cookie, gravel, soil.
Homogeneous- same composition throughout.
Kool-aid, air.
Every part keeps its properties.

37. What are homogeneous mixtures?
Solutions are homogeneous mixtures. Solution particles are very small and compose molecules, atoms, or ions.
Colloids are homogeneous mixtures. Colloid particles are larger than solution particles but do not settle as suspension do.
Examples of colloids are fog, mayonnaise, jello, whipped cream.
What is the Tyndall Effect and Brownian motion?

38. What are heterogeneous mixtures?
Heterogeneous mixtures (suspensions) are made of larger particles than that of homogeneous mixtures. These particles remain suspended temporarily and will eventually settle or separate.
Examples are chocolate milk, orange juice, muddy water.

39. What are liquid mixtures?
Liquids which evenly mix are said to be miscible. Gasoline, antifreeze and water.
Liquids which do not mix are said to be immiscible. Oil and water; oil and vinegar.
Can gases mix with liquids?
How do fish breathe?
What are carbonated soft drinks?

40. Phases
A part of a sample with uniform composition, therefore uniform properties
Homogeneous- 1 phase
Heterogeneous – more than 1

41. Separating mixtures Only a physical change- no new matter
Filtration- separate solids from liquids with a barrier
Distillation- separate because of different boiling points
Heat mixture
Catch vapor in cooled area
Chromatography- different substances are attracted to paper or gel, so move at different speeds

42. Chromatography

43. How can physical changes be used to separate mixtures?
Impurities mixed with water can be separated by distillation.
What is distillation?
Distillation is a process of separating parts of a mixture by differences in boiling points.

44. Solutions Homogeneous mixture Mixed molecule by molecule
Can occur between any state of matter.
Solid in liquid- Kool-aid
Liquid in liquid- antifreeze
Gas in gas- air
Solid in solid - brass
Liquid in gas- water vapor

45. Solutions
Like all mixtures, they keep the properties of the components.
Can be separated by physical means
Not easily separated- can be separated without creating anything new.

46. Chemical Reactions Another name for chemical change
When one or more substances are changed into new substances.
Reactants- stuff you start with
Products- What you make
NEW PROPERTIES
Because each substance has its own properties

47. Indications of a chemical reaction
Energy absorbed or released
Color change
Odor change
Precipitate- solid that separates from solution
Not easily reversed
Only clues not certainty

48. Chemical symbols There are 116 elements
Each has a 1 or two letter symbol
First letter always capitalized second never
Some from Latin or other languages

49. Chemical symbols Used to write chemical formulas
Subscripts tell us how many of each atom
H2O
C3H8
HBrO3

50. Conservation of Mass
Mass can not be created or destroyed in ordinary (not nuclear) changes.
All the mass can be accounted for.
Mass at the start = mass at end

51. The Law of Conservation of Mass
Matter cannot be created nor destroyed.

52. Energy The ability to do work.
Work - cause a change or move an object.
Many types- all can be changed into the other.

53. Types of energy Potential- stored energy
Kinetic Energy- energy something has because its moving
Heat- the energy that moves because of a temperature difference.
Chemical energy- energy released or absorbed in a chemical change.
Electrical energy - energy of moving charges

54. Types of Energy
Radiant Energy- energy that can travel through empty space (light, UV, infrared, radio)
Nuclear Energy – Energy from changing the nucleus of atoms
All types of energy can be converted into others.
If you trace the source far enough back, you will end up at nuclear energy.

55. Conservation of Energy
Energy can be neither created or destroyed in ordinary changes (not nuclear), it can only change form.
Its not just a good idea, its the law.

56. What about nuclear? E = mc2 energy = mass x (speed of light)2
speed of light = 3 x 108
A little mass can make a lot of energy
Law of Conservation of Mass - Energy the total of the mass and energy remains the same in any change