1. Chemistry is a physical science
Chemistry – the study of the composition,
structure, and properties of matter and the
changes it undergoes

2. Physical and Chemical Changes
Matter
Physical and Chemical Changes
Pure Substances
Mixtures
States of Matter

3. Everything that has mass and volume is called matter.
What is matter?
Everything that has mass and volume is called matter.
mass is the measure of the amount of matter
Basic definition of matter.
Volume is the measure of how much space it
takes up

4. The Four States of Matter
Chemistry
The Four States of Matter

5. The Four States of Matter
Solid
Liquid
Gas
Plasma

6. States of Matter The Four States of Matter
Basis of Classification of the Four Types
Based upon particle arrangement
Based upon energy of particles
Based upon distance between particles

7. States of Matter Solids
Particles of solids are tightly packed, vibrating about a fixed position.
Solids have a definite shape and a definite volume.
Solids have an infinite number of free surfaces.

8. Particle Movement Examples
States of Matter
Solids
Particle Movement Examples

9. States of Matter Liquids
Particles of liquids are tightly packed, but are far enough apart to slide over one another.
Liquids have an indefinite shape and a definite volume.
(take the shape of its Container
Liquids have one free surface.

10. Particle Movement Examples
States of Matter
Liquids
Particle Movement Examples

11. States of Matter
Gases
Particles of gases are very far apart and move freely.
Gases have an indefinite shape and an indefinite volume.
Gases have no free surfaces.

12. Particle Movement Examples
States of Matter
Gases
Particle Movement Examples

13. States of Matter Plasma A plasma is an ionized gas.
A plasma is a very good conductor of electricity and is affected by magnetic fields.
Plasma, like gases have an indefinite shape and an indefinite volume.

14. States of Matter Plasma Particles
The negatively charged electrons (yellow) are freely streaming through the positively charged ions (blue).

15. States of Matter
Plasma
Examples

16. States of Matter The Four States of Matter
The Classification and Properties of Matter Depend Upon Microscopic Structure
Particle arrangement
Particle energy
Particle to particle distance

17. 3 Classes of Matter Elements, Compounds and Mixtures 1. Elements
a. 92 naturally Occurring Elements
b. anything above 92 are man-made

18. Elements are represented by chemical symbols - the first letter is
always capitalized the second letter is never capitalized
H - hydrogen
Pb - lead
a. arranged on the periodic table by atomic number
b. groups and families - vertical
c. periods - horizontal rows
d. Homogenous – uniform through out

19. 3 classes of elements metals 1. have luster - shinny
2. are malleable - hammered into shape
3. good conductors of heat and electricity
4. are ductile - able to be drawn into wire

20. nonmetals
1. lack luster
2 hard and brittle
3. poor conductors - good insulators
4. non ductile
5. many are gases
metalloids - have properties of both

21. 3 Classes of Matter 2. compounds
a. two or more elements chemically combined
b. properties of elements are destroyed
c. Law of definite composition -
proportions elements of compounds are always the same
d. represented by chemical formulas
H2O - the 2 is known as a subscript and
tells the number of atoms in the compound
which proceeds it.

22. 3 Classes of Matter 3. mixtures - two or more substances mixed
together
substances that are mixed together
retain their own properties
b. ice tea, chocolate milk
c. do not follow the law of definite
composition

23. d. heterogeneous - non-uniform
i. sand and water, peanut butter and jelly
e. can be separated by physical means
i. magnetism, filtering, evaporation

24. II. Energy
A. ability to do work
1. work -only done when an object is moved
B. energy transfer - energy flows from a high concentration to a low concentration of energy
1. heat - hot objects makes cold object warmer and therefore cause objects to become cooler

25. 2. joule is the SI unit for energy
3. calorie is still used - the amount of heat required to raise 1 gram of water 1 degree Celsius
a. a food Calorie is 1000 time larger

26. 4. endothermic - absorbs heat
5. exothermic - releases heat
6. activation energy - energy required to get a reaction going
7. specific Heat - the amount of heat required to raise 1 gram of a substance 1 degree Celsius

27. What are "substances"?
Substances can be identified as either an element, compound, or a mixture.

28. Characteristics of Mixtures
Variable composition
Components retain their characteristic properties
May be separated into pure substances by physical methods
Mixtures of different compositions may have widely different properties
Basic identification of a mixture.

29. Characteristics of Pure Substances
Fixed composition
Cannot be separated into simpler substances by physical methods (physical changes)
Can only be changed in identity and properties by chemical methods
Properties do not vary
Basic characteristics of pure substance:

30. What is a pure substance?
Compounds
Can be decomposed into simpler substances by chemical changes, always in a definite ratio
Elements
Cannot be decomposed into simpler substances by chemical changes
The two categories of pure chemical substances.

31. Homogenous Mixtures
Homogenous mixtures look the same throughout but can be separated by physical means (dissolution, centrifuge, gravimetric filtering, etc.). Examples: milk, yogurt

32. Indicators of Homogenous Mixtures
Have the same composition throughout
Components are indistinguishable
May or may not scatter light
Examples: milk, yogurt, etc.
Brainstorm more examples of homogenous mixtures.

33. What is a mixture?
Mixtures are two or more substances that are NOT chemically combined.
Mixtures do not:
·      Have constant boiling points
·      Have constant melting points

34. What are solutions?
Solutions are homogenous mixtures that do not scatter light. These mixtures are created when something is completely dissolved in pure water. Therefore, they are easily separated by distillation or evaporation.
Examples: sugar water, salt water

35. Heterogenous Mixtures
Heterogeneous mixtures are composed of large pieces that are easily separated by physical means (ie. density, polarity, metallic properties).

36. Indicators of Heterogenous Mixtures
Do not have same composition throughout
Components are distinguishable
Examples: fruit salad, vegetable soup, etc.
Brainstorm more examples of heterogenous mixtures.

37. Remember Elements quiz next Monday
September 12, 2011

38. What are colloids?
Colloids are solutions. They can be described as a substance trapped inside another substance. They can be identified by their characteristic scattering of light.
For example: air trapped inside the fat molecules in whipped cream.
Brainstorm more ideas of colloids: fog, egg merangue, jello, smoke, etc.

39. What is a physical change?
A physical change occurs when the substance changes state but does not change its chemical composition. For example: water freezing into ice, cutting a piece of wood into smaller pieces, etc. The form or appearance has changed, but the properties of that substance are the same (i.e. it has the same melting point, boiling point, chemical composition, etc.)
Definition of physical changes.

40. Characteristics of Physical Changes
Melting point
Boiling point
Vapor pressure
Color
State of matter
Density
Electrical conductivity
Solubility
Adsorption to a surface
Hardness
Physical changes are characterized by the following:

41. What are chemical changes?
A chemical change occurs when a substance changes into something new. This occurs due to heating, chemical reaction, etc. You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes. Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc).
Definition of chemical change.

42. Characteristics of Chemical Changes
Reaction with acids
Reaction with bases (alkalis)
Reaction with oxygen (combustion)
Ability to act as oxidizing agent
Ability to act as reducing agent
Reaction with other elements
Decomposition into simpler substances
Corrosion
Chemical Changes are characterized by the following:

43. Intensive and Extensive Properties
Physical and chemical properties may be intensive or extensive.

44. What are intensive properties?
Intensive properties such as density, color, and boiling point do not depend on the size of the sample of matter and can be used to identify substances.

45. What are extensive properties?
Extensive properties such as mass and volume do depend on the quantity of the sample.

46. How can we identify physical properties?
Physical properties are those that we can determine without changing the identity of the substance we are studying.

47. Examples of physical properties:
The physical properties of sodium metal can be observed or measured. It is a soft, lustrous, silver-colored metal with a relatively low melting point and low density.
Hardness, color, melting point and density are all physical properties.

48. What are chemical properties?
Chemical properties describe the way a substance can change or react to form other substances. These properties, then, must be determined using a process that changes the identity of the substance of interest.

49. How can chemical properties be identified?
One of the chemical properties of alkali metals such as sodium and potassium is that they react with water. To determine this, we would have to combine an alkali metal with water and observe what happens.
In other words, we have to define chemical properties of a substance by the chemical changes it undergoes.

50. Comparison of Physical and Chemical Properties

51. Conservation of Matter
Law of
Conservation of Matter
There is no observable change in the quantity of matter during a chemical reaction or a physical change.
In other words, matter cannot be created nor destroyed. It is just converted from one form to another
Definition of Conservation of matter.

53. Need Books Today
Homework – page 26
Questions 1,5,6,8,11-14,18-24
Due tomorrow Sept

54. Properties of Matter

55. What kind of changes does matter undergo?
All matter, regardless of state, undergoes physical and chemical changes. These changes can be microscopic or macroscopic.

56. Microscopic Explanation for Properties of Liquids
States of Matter
Microscopic Explanation for Properties of Liquids
Liquids have an indefinite shape because the particles can slide past one another.
Liquids are not easily compressible and have a definite volume because there is little free space between particles.
Liquids flow easily because the particles can move/slide past one another.

57. Microscopic Explanation for Properties of Solids
States of Matter
Microscopic Explanation for Properties of Solids
Solids have a definite shape and a definite volume because the particles are locked into place
Solids are not easily compressible because there is little free space between particles
Solids do not flow easily because the particles cannot move/slide past one another

58. Microscopic Explanation for Properties of Gases
States of Matter
Microscopic Explanation for Properties of Gases
Gases have an indefinite shape and an indefinite volume because the particles can move past one another.
Gases are easily compressible because there is a great deal of free space between particles.
Gases flow very easily because the particles randomly move past one another.

59. Microscopic Explanation for Properties of Plasmas
States of Matter
Microscopic Explanation for Properties of Plasmas
Plasmas have an indefinite shape and an indefinite volume because the particles can move past one another.
Plasmas are easily compressible because there is a great deal of free space between particles.
Plasmas are good conductors of electricity and are affected by magnetic fields because they are composed of ions (negatively charged electrons and positively charged nuclei).