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Chap2 Outline

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Chap2 Outline

Objectives    Chapter 2 Outline

2.1 What is Matter?    2.2 How do Matter and Energy Interact?

2.3 How is Matter Classified?    2.4 How are Substances Identified

2.5 How should Data be Reported?    (Covered in Calculation Unit)

Objectives

2.1  What is matter?

1.                  describe matter by its properties.

2.                  define mass, and state how to measure it.

3.                  distinguish between chemical and physical properties, and give examples of each.

4.                  draw models to represent solids, liquids, and gases on the particle level.

2.2  How do matter and energy interact?

1.                  distinguish among kinetic, potential, and other forms of energy.

2.                  apply the conservation of energy and matter to systems.

3.                  describe the energy changes that accompany changes of state.

4.                  describe energy transfers in chemical reactions.

2.3  How is matter classified?

1.                  distinguish between pure substances and mixtures on the particle level.

2.                  classify mixtures as heterogeneous or homogeneous.

3.                  distinguish among atoms, elements and compounds.

4.                  explain how compounds can be distinguished from mixtures.

2.4  How are substances identified?

1.                  list five methods of separating the components of a mixture.

2.                  list properties that can be used to identify a pure substance.

3.                  calculate density and use density to identify pure substances.

4.                  determine the identity of substances when given adequate information.

 

Chemistry Chapter 2 Notes - Matter and Energy

2-1 What is Matter?

2-2 How do matter and energy interact?

2-3 How is matter classified?

2-4 How are substances identified?

2-5 How should data be reported?

 

2-1 What is matter?

Objectives: SWBAT

1. describe matter by its properties.

2. distinguish between weight and matter.

3. define mass, and state how to measure it.

4. distinguish between chemical and physical properties, and give examples of each.

5. draw models to represent solids, liquids, and gases on the particle level.

 

A. Matter: Anything that has mass and volume.

1. Volume: The amount of space an object occupies.

2. Mass: The quantity of matter in an object.

3. Weight: The effect of gravity on an object.

a. Mass is constant anywhere in the universe. Usually measured by comparing with know masses (Balances).

b. Weight changes depending upon the force of gravity. Usually measured using springs to measure force (Scales).

B. Properties of Matter:

1. Physical Properties: Properties that can be observed without changing the identity of the object.

a. Extensive Properties: Physical Properties are dependent upon the quantity of matter present. (Volume, Length, Heat, & Mass)

Intensive Properties: A property that does not change when the quantity of matter changes. Usually depends upon the identity of the object, not the quantity. Many of these are some of the properties we use to identify substances!

 

 

 

 

 

 

1) Electrical Conductivity: Ability to carry a current.

2) Heat Conductivity: Ability to carry heat.

3) Density: The ration of mass to volume.

4) Melting Point (Freezing Point): The temperature that liquids change to a solid or from a solid to a liquid.

5) Boiling Point (Condensation Point): The temperature that liquids change to gases or gases change to liquids.

6) Index of Refraction: The extent which transparent materials "bend" light.

7) Malleability: The ability to be hammered into thin sheets.

8) Ductility: The ability to be drawn into a thin wire.

9) Magnetism: The ability to be turned into a Magnet.

10) Solubility: The ability to be dissolved into different solvents.

11) Color: The wavelengths of light reflected by an object.

12) Temperature: The average kinetic energy of a substance.

2. Chemical Properties: Properties that can be observed only when substances interact with other substances.

a. Corrosion

b. Flammability (Combustion, Burning)

c. Electrolysis

d. Effervescence

e. Precipitation:

C. Matter Changes: (Section 2-3 in book pg 44)

1. Physical Change: A change that does not effect the identity of the substance.

a. Cutting paper, melting ice, shoveling dirt, bending metal, change of state, dissolving substances, heating, etc.

b. Changes of state: Kinetic Theory

2. Chemical Change: A change that produces one or more new substances.

a. Evidence of Chemical Changes:

1) Change in intensive properties.

2) Gases being formed without heating.

3) Precipitate forming.

4) Change in color.

5) Energy produced or absorbed.

a) Change in temperature. **Burning**

b) Production of light.

c) Production of sound. **Explosion**

Exp 2A: Chemical or Physical Change Lab

Pg 39 1-4 (5 is story link)

Pg 66 #1-9

2-2 Energy in Reactions

Objectives: SWBAT

1. distinguish among kinetic, potential, and other forms of energy.

2. apply the conservation of energy and matter to systems.

3. describe the energy changes that accompany changes of state.

4. describe energy transfers in chemical reactions.

A. Potential Energy (PE): Stored Energy.

B. Kinetic Energy (KE): Energy in Motion. KE = ½ mv2

1.  Law of Conservation of Energy: Except for nuclear reactions, energy is neither created nor destroyed. The total amount of energy is constant.

a. The total energy of a system is equal to the potential energy + kinetic energy.

C. Temperature: A measurement of the motion of molecules. Temperature measures the intensity (concentration) of heat.

D. Heat: Measures the total thermal energy of a system. Heat depends on both the quantity of matter and the heat storage capacity (Specific Heat) of matter.

1. Difference between Heat and Temperature:

a. These are related, but are not the same.

b. Temperature is a reflection of the heat energy of a system, but is a measurement of the heat concentration or intensity.

c. The amount of heat is the total amount of energy of a system and is dependent on:

1) The temperature of the matter.

2) The mass of the matter.

3) The heat storage capacity (Specific Heat) of the matter.

2. Temperature Scales

a. C (1.8) + 32 = F

b. F –32 (.555) = C

Demo: Burn Steel Wool

E. Distinguish between the quantities and intensities of energy?

Transparency:

1. Which of the following has the most heat? Temperature?

a. A cup with 50 mL of water at 20 C

b. A cup with 50 mL of water at 20 C

2. Which of the following has the most heat? Temperature?

a. A cup with 50 mL of water at 20 C

b. A bucket with 50 mL of water at 20 C

3. Which of the following has the most heat? Temperature?

a. A full bucket of water at 20 C

b. A full cup of water at 20 C

4. Which of the following has the most heat? Temperature?

a. A cup with 50 mL of water at 25 C

b. A cup with 50 mL of water at 20 C

5. Which of the following has the most heat? Temperature?

a. A cup with 100 mL of water at –150C

b. A cup with 100 mL of water at –100 C

6. Which of the following has the most energy?

a. A cup with 50 mL of water at 20 C

b. A cup with 50 mL of water at 70 C

7. Which has the most energy?

a. A cup with 100 mL of water at 20 C

b. A cup with 50 mL of water at 20 C

8. Which of the following has the most energy?

a. A cup with 50 mL of water at 20 C

b. A cup with 50 mL of alcohol at 20 C

 

F. Kinetic Theory: States of Matter

 

G. Chemical Reactions:

1. For Chemistry when you describe heat and temperature do not use terms like hot, cold, cool, etc. Remember that heat is measuring the total amount of energy, while temperature measures the intensity of heat. Cold is the absence of heat.

2. If we pour together two reactants and observe temperature going up what is happening?

a. /---->Difference = 50 kJ given off as heat

b. Reactants 100 kJ -----------> Products 50 kJ

3. Exothermic Change: Energy is released to the surroundings (usually in the form of heat). Temperature usually increases, -D H.

4. If we pour together two reactants and observe that the temperature dropped, what is happening?

a. Difference is taken from environment -------\

1) Reactants 125 kJ ---------> Products 200 kJ

5. Endothermic Change: Energy is absorbed from the surroundings (usually in the form of heat). Temperature decreases, +D H.

Need to develop a Heat/Temperature Distinguishment Lab

Pg 43 # 6-7 (8 is Story Link)

Pg 45 9-11

Pg 66 # 10 - 21

 

2-3 How is matter classified?

Objectives: SWBAT

1. distinguish between pure substances and mixtures on the particle level.

2. classify mixtures as heterogeneous or homogeneous.

3. distinguish among atoms, elements and compounds.

4. explain how compounds can be distinguished from mixtures.

A. Mixtures and pure substances:

1. Pure substances: matter is composed of only one kind of atom or compound.

a. Elements: composed of the same type of atom.

1) Elements are the simplest pure substances.

2) Review: Chemical Symbols: First letter is capitalized, all others are small!

3) Elements may consist of single atoms or of groups of atoms (molecules).

4) Allotropes: different molecular forms of an element in the same physical state. Examples:

a) Oxygen: Nascent (O), Oxygen (O2) & Ozone (O3)

b) Carbon: graphite, diamonds, bucky ball, buckytube, & coal.

b. Compounds/Molecules: a small group of atoms held together by a chemical bond. These are pure substances usually composed of two or more types of atoms (elements).

2. Mixture: a collection of two or more pure substances physically mixed together.

a.

Homogeneous: Contains only one phase.

1) Solutions: a homogeneous mixture that consists of substances mixed on the scale of individual particles. Solutions are always homogeneous.

b.

Heterogeneous: Contains more than one phase. Mixtures are always heterogeneous.

1) Phase: any part of a system that has uniform composition and properties.

 

Homogeneous Mixture

Heterogeneous Mixture

Solutions

Oil & Vinegar

Gasoline

Salad

Tea

Bread Dough

Vinegar

Plastic Squeeze containers

Sea Water

Concrete

2) It is very hard to tell the difference without laboratory testing.

B. Three principal differences between compounds and mixtures:

1. Mixtures are never made of only a single compound.

2. The properties of a mixture reflect the properties of the substances it contains, but the properties of a compound often bear no resemblance to the properties of the elements that compose it.

3. Compounds have a definite composition by mass of their combining elements (This is called the Law of Definite Proportions). The iron-sulfur compound pyrite has a definite composition. The mass of pyrite is always 46.55% iron and 53.45% sulfur. In contrast, substances in a mixture can exist in any mass ratio.

C. Predicting Properties of Homogeneous Mixtures

1. Homogeneous Mixtures have intensive properties that are proportional to their mixtures.

Experiment 2B: Properties of Homogeneous Mixtures

Need to develop:

Need worksheet:

Pg 51 #15-17 (18&19 Story Link)

Pg 67 #22-28

2-4 How are substances identified?

Objectives: SWBAT

1. list five methods of separating the components of a mixture.

2. list properties that can be used to identify a pure substance.

3. calculate density and use density to identify pure substances.

4. determine the identity of substances when given adequate information.

A. Use Some Intensive Properties. Those intensive properties that depend upon the structure of matter.

B. Use Chemical Properties: These depend upon the identity of matter.

C. Methods of separating mixtures:

1. Mixtures can be separated by physical means using the differences in the intensive properties of the materials of the mixture.:

a. Filter (uses solubility)

1) Solid & Liquid

2) Sand & Gravel

3) Sand & Salt

b. Evaporation (uses heat to evaporate the solvent in a solution)

1) Salt in water

c. Distillation (uses the difference in boiling points)

1) Water and alcohol

d. Centrifuge (uses the difference in density)

e. Decant (uses the differences in solubility & density

1) Water and oil

f. Chromatography (uses the difference in solubility)

Experiment 2D: Paper Chromatography

Experiment 2E: Murder In Opulance

Pg 57 #20-22 (23 Story Link)

Pg 67 #32-38

2-5 How should data be reported?

A. Reliability of measurements: Are measurements being recorded properly and made using good laboratory techniques?

1. Accuracy: the extent to which a measurement approaches the true value of a quantity. Relate to the Chemical or Physical Change Lab

2. Precision: the degree of exactness of refinement of a measurement.

3. Use the analogy of a bulls eye target to illustrate.

4. Experiment 2A Accuracy

B. Laboratory Equipment: In this class we will use the smallest division of the scale of an instrument as the accuracy of the instrument.

C. Standard Units.

D. Graphing (see pg 800, Appendix B)

Pg 62 #24-31 (Significant Figures)

Pg 67 #39-52

 

Chapter 2 Review WS

Chapter 2 Review

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Last modified: December 08, 2001