1. Chem EOG review

2. 3 classifications of matter
Elements, compounds, mixtures

3. Element: made of one kind of atom Ex: Cu, O₂, Fe Compound:
Made of two or more elements chemically joined together
Has a fixed composition (ratio) of elements
Has different properties than the elements that make it.
Can only be broken down into elements by a chemical reaction. Ex: H₂O
Mixture:
Two or more different elements and/or compounds that are physically combined, NO CHEMICAL BONDING
Can be homogeneous or heterogeneous
Homogeneous (same throughout, solid/liquid/gas…ex: alloy, air)
Heterogeneous (different throughout…pizza, muddy water)
Can be easily separated into parts by physical methods (evaporation, chromatography, magnetism, filter)
Often retains the properties of its components

4. Elements
pure substance that cannot be separated into simpler substance by physical or chemical means.

5. NaCl H2O CO2 ≠ CO Compounds
Pure substance composed of two or more different elements joined by chemical bonds. Two compounds made of different quantities of the same elements will have different properties
Made of elements in a specific ratio
that is always the same
Has a chemical formula
Can only be separated by
chemical means, not physically
CO2
≠ CO

6. Mixtures
A combination of two or more pure substances that are not chemically combined.
substances held together by physical forces, not chemical
No chemical change takes place
Each item retains its properties
in the mixture
They can be separated physically
Chem4kids.com

7. Can you identify the following?
You will be shown a series of photos. Tell if each photo represents an item composed of an element, compound, or mixture.
Review:
An element contains just one type of atom.
A compound contains two or more different atoms joined together.
A mixture contains two or more different substances that are only physically joined together, not chemically.
A mixture can contain both elements and compounds.
Homogeneous
Heterogeneous

8. Element, Compound, or Mixture?
Copper

9. Element, Compound, or Mixture?
Copper Cu

10. Element, Compound, or Mixture?
Jelly Beans

11. Element, Compound, or Mixture?
Jelly Beans

12. Element, Compound, or Mixture?
Table Sugar

13. Element, Compound, or Mixture?
Table Sugar
C12H22O11

14. Element, Compound, or Mixture?
Tea

15. Element, Compound, or Mixture?
Tea

16. Element, Compound, or Mixture?
Salt

17. Element, Compound, or Mixture?
NaCl
Salt

18. Element, Compound, or Mixture?
Neon Gas

19. Element, Compound, or Mixture?Ne
Neon Gas

20. Element, Compound, or Mixture?
Salad

21. Element, Compound, or Mixture?
Salad

22. Element, Compound, or Mixture?
Pure Water

23. Element, Compound, or Mixture?
Pure Water
H2O

24. Element, Compound, or Mixture?
Aluminum

25. Element, Compound, or Mixture?
Aluminum Al

26. Element, Compound, or Mixture?
Silver

27. Element, Compound, or Mixture?
Silver Ag

28. Element, Compound, or Mixture?
Sand

29. Element, Compound, or Mixture?
Sand

33. Practice questions

38. Atom: basic unit of matter Element: A chemical element, or element for short, is a type of atom that is defined by its atomic number

39. Parts of atoms
Proton + : large, positively charged subatomic particle, found in the nucleus Neutron 0 : large, neutral (no charge) subatomic particle, found in the nucleus Electron - : very small, negatively charged subatomic particle, located outside the nucleus in the large area called the electron cloud

41. Groups A group, also known as a family, is a vertical column in the periodic table of the elements. Groups are considered the most important way of classifying the elements. Elements within the same group have the same number of valence electrons, which is why they have similar chemical properties.

42. Periods A period is a horizontal row in the periodic table of the elements. The period number is equivalent to the number of electron energy levels (rings) in the element.

43. Number of protons
Number of electrons
Number of protons + neutrons
Doesn’t include electrons because
they weigh next to nothing
TRY IT

44. Metals Conduct heat Conduct electricity Malleable Ductile Shiny
Form + ions
Iron, sodium, aluminum, gold

45. Metal families Alkali Group 1 extremely reactive
Alkaline Earth Group 2
also very reactive
Transition metals groups 3-12
not very reactive, used more commonly in industry
ex: gold, silver, iron

46. Nonmetals Insulators (Do not conduct heat or electricity) Brittle
Dull in appearance
Form – ions
Chlorine, bromine, neon, oxygen
Many are gases at room temperature

47. Nonmetal families Halogens group 17 extremely reactive
used in cleaning agents
Ex: chlorine (Cl)
Noble Gases group 18
do not combine to form molecules or compounds, exist as single atoms because they are stable. Noble gases have a complete (full) outer ring of electrons

48. Metalloids Found along the zig zag line
Have properties similar to both metals and non metals
Used in semiconductors
Silicon (Si)

49. Atoms act toward stability and neutrality
Stability = complete outer ring of electrons (2,8,8) Atoms combine with other atoms to complete their outer ring of electrons Neutrality= atoms seek an overall neutral charge which they can achieve by having the same number of protons (+) and electrons (-)

50. Atom Identity!! TRY IT
Proton number (Atomic Number) identifies the atom. Atoms of the same element don’t always have the same number of neutrons…..same proton number but different neutron number = isotopes.

51. Compounds or molecules are represented using a chemical formula
Subscripts (little number) tell you the number of atoms in the 1 molecule of the compound
Coefficients (big number out front) tell you how many molecules
(no number means the number is 1!)

52. practice

56. Conservation of Mass
Mass on the reactant side of the equation equals the mass on the product side of the equation Number and type of atoms on the reactant side of the equation equals the number and type of atoms on the product side of the equation. Reactants Products

57. To check for balance, multiply coefficient x subscript
Are these balanced?
3K + 2B2O3  2K2O + 2B
2Fe + 3Cl2 2FeCl3
KMnO4 +2HCl  KCl + MnCl2 + H2O + Cl2
2C6HCOOH + 13O2  13CO2 + 2H2O
To balance an equation its cool to change coefficients, do not change subscripts….don’t mess w/the little people (you’ll change the molecule’s identity!)

58. A reaction has 4 lead atoms in the products, according to the law of conservation of mass, how many lead atoms will be in the reactants? In a reaction, the mass of the reactants is 24g and 8g. Three products are formed, if the mass of two products is 3g and 7g, what is the mass of the third product?

59. practice

65. State of matter (solid, liquid, gas) Melting, freezing, boiling point
Elements and compounds can be described by their chemical and physical properties
Physical property: characteristic of a substance you can observe (using your senses) without changing it into something else
State of matter (solid, liquid, gas)
Melting, freezing, boiling point
Magnetism
Density
Color
Shape
Malleability
Solubility
Specific heat

66. Chemical properties: properties of an element or compound in a chemical reactionpH
Reactivity
Flammability

67. Practice on Identifying Chemical and Physical Properties
Water boils at 100 degrees Celsius.
Diamonds are capable of cutting glass.
Water can be separated by electrolysis into hydrogen and oxygen.
Sugar is capable of dissolving in water.
Vinegar will react with baking soda.
Yeast acts on sugar to form carbon dioxide and ethanol.
Wood is flammable.
Aluminum has a low density.
Ammonia is a gas at room temperature.
Bromine has a red color.

68. Changes can be physical or chemical
Physical changes do not rearrange atoms, I have the same substance I started with. I can reverse a physical change Change in shape Change in phase Dissolving These are easily Reversable

69. Chemical change: atoms are rearranged, I have different substances at the end of a chemical reaction/change
Change in color
Formation of precipitate (L+LS)
Formation of a gas
Creation of light
Burning
Change in temperature (exothermic, endothermic)

70. Practice on Identifying Chemical and Physical Changes
You drop the spoon in the disposal and it bends
Koolaid is dissolved in water
Wood in a woodpile begins to decompose
A campfire
The process of respiration takes sugar and oxygen and creates water and carbon dioxide
Making coffee
Lightning converts N2 in the atmosphere to NO3

71. Energy in a chemical reaction
Exothermic: releases more energy than it took to start
Gets warm or releases light
Endothermic: absorbs more energy than it releases
Gets cold

72. RRR Questions