1. Science, Systems, Matter, and Energy
Chapter 2
Science, Systems, Matter, and Energy

2. TYPES AND STRUCTURE OF MATTER
Elements and Compounds
Matter exists in chemical forms as elements and compounds.
Elements (represented on the periodic table) are the building blocks of matter.
Compounds: two or more different elements held together in fixed proportions by chemical bonds.

3. Basic Chemistry Matter, Mass, and Weight Elements and Atoms
Matter: Anything that occupies space and has mass
Mass: The amount of matter in an object
Weight: The gravitational force acting on an object of a given mass
Elements and Atoms
Elements: The simplest type of matter with unique chemical properties
Atoms: Smallest particle of an element that has chemical characteristics of that element

4. Atoms
Figure 2-4

5. Atomic Structure Atoms: composed of subatomic particles Nucleus
Neutrons: no electrical charge
Protons: positive charge
Electrons: negative charge
Nucleus
Formed by protons and neutrons
Most of volume of atom occupied by electrons

6. Atomic Number and Mass Number
Atomic Number: Equal to number of protons in each atom which equals the number of electrons
Mass Number: Number of protons plus number of neutrons

7. Isotopes and Atomic Mass
Isotopes: Two or more forms of same element with same number of protons and electrons but different neutron number
3 types of hydrogen
Denoted by using symbol of element preceded by mass number as 1H, 2H, 3H
Atomic Mass: Average mass of naturally occurring isotopes

9. Molecules and Compounds
Molecules: Two or more atoms form a covalent bond
Example: Water
Compounds: A substance composed of two or more different types if atoms chemically combined
Example: Hydrogen Molecule
Molecular Mass: Determined by adding up atomic masses of its atoms or ions
Example: NaCl ( )

11. Covalent Bonding Atoms share one or more pairs of electrons
Single covalent: Electron pair between 2 atoms
Double covalent: Two atoms share 4 electrons
Nonpolar covalent: Electrons shared equally
Polar covalent: Electrons not shared equally

12. Electrons and Chemical Bonding
Ion: When an atom loses or gains electrons and become charged
Cation: Positively charged ion
Anion: Negatively charged ion
Ionic Bonding
Cations and anions are attracted to each other

13. Ions
An ion is an atom or group of atoms with one or more net positive or negative electrical charges.
The number of positive or negative charges on an ion is shown as a superscript after the symbol for an atom or group of atoms
Hydrogen ions (H+), Hydroxide ions (OH-)
Sodium ions (Na+), Chloride ions (Cl-)

14. Compounds and Chemical Formulas
Chemical formulas are shorthand ways to show the atoms and ions in a chemical compound.
Combining Hydrogen ions (H+) and Hydroxide ions (OH-) makes the compound H2O (dihydrogen oxide, a.k.a. water).
Combining Sodium ions (Na+) and Chloride ions (Cl-) makes the compound NaCl (sodium chloride a.k.a. salt).

15. Synthesis and Decomposition Reactions
Synthesis Reactions
Two or more reactants chemically combine to form a larger product
Decomposition Reactions
Reverse of synthesis reactions

16. Acids and Bases; Salts and Buffers
Acid: A proton donor or any substance that releases hydrogen ions
Bases: A proton acceptor or any substance that binds to or accepts hydrogen ions
Buffers: Able to maintain the pH

17. The pH Scale Refers to the Hydrogen ion concentration in a solution
Neutral: pH of 7 or equal hydrogen and hydroxide ions
Acidic: a greater concentration of hydrogen ions
Alkaline or basic: a greater concentration of hydroxide ions

18. The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution.
Figure 2-5

19. Chemistry
Inorganic Chemistry: Generally substances that do not contain carbon
Water
Oxygen
Organic Chemistry: Study of carbon-containing substances

20. Organic Compounds: Carbon Rules
Organic compounds contain carbon atoms combined with one another and with various other atoms such as H+, N+, or Cl-.
Contain at least two carbon atoms combined with each other and with atoms.
Methane (CH4) is the only exception.
All other compounds are inorganic.

21. Organic Chemistry Carbohydrates Lipids Proteins
Composed of carbon, hydrogen, oxygen
Lipids
Composed mostly of carbon, hydrogen, oxygen
Proteins
Composed of carbon, hydrogen, oxygen,nitrogen
Nucleic Acids: DNA and RNA
Composed of carbon, hydrogen, oxygen, nitrogen, phosphorus
Adenosine Triphosphate (ATP)
Composed of adenosine and three phosphate groups

22. Carbohydrates Monosaccharides or building blocks Disaccharides
Simple sugars: glucose, fructose, galactose
Disaccharides
Two simple sugars bound together by dehydration: sucrose, lactose, maltose
Polysaccharides
Long chains of many monosaccharides: glycogen in animals; starch and cellulose in plants

23. Lipids
Lipids: Can be dissolved in nonpolar organic solvents as alcohol or acetone but relatively insoluble in water
Fats, Oils and Waxes.
Triglycerides: composed of glycerol and fatty acids
Phospholipids: Important structural component of cell membranes
Steroids: Cholesterol, bile salts, estrogen, testosterone
Fat-soluble Vitamins

24. Proteins Amino acids: The building blocks of protein
Peptide bonds: Covalent bonds formed between amino acids during protein synthesis
Structure
Primary, secondary, tertiary, quartenary
Enzymes: Protein catalysts
Lock-and-key model
Active site
Coenzymes

25. Protein Structure and Enzyme Action

26. Nucleic Acids: DNA and RNA
DNA: Deoxyribonucleic acid
Genetic material of cells copied from one generation to next
Composed of 2 strands of nucleotides
Each nucleotide contains one of the organic bases of adenine or guanine which are purines and thymine or cystosine which are pyrimidines
RNA: Ribonucleic acid
Similar to a single strand of DNA
Four different nucleotides make up organic bases except thymine is replaced with uracil (pyrimidine)

27. DNA Structure

28. Water Inorganic Stabilizes body temperature Protection
Necessary for many chemical reactions of life
Mixing Medium
Mixture: Substance physically but not chemically combined
Solution: Liquid, gas, or solid uniformly distributed
Solvent: What dissolves the solute
Solute: What is to be dissolved

30. Acids and Bases; Salts and Buffers
Acid: A proton donor or any substance that releases hydrogen ions
Bases: A proton acceptor or any substance that binds to or accepts hydrogen ions
Salts: A cation consisting of other than a hydrogen ion and other than an anion or hydroxide ion
Buffers: A solution of a conjugate acid-base pair in which acid and base component occur in similar concentrations

31. The pH Scale Refers to the Hydrogen ion concentration in a solution
Neutral: pH of 7 or equal hydrogen and hydroxide ions
Acidic: a greater concentration of hydrogen ions
Alkaline or basic: a greater concentration of hydroxide ions

32. Energy Energy: The capacity to do work Potential Energy: Stored energy
Kinetic Energy: Does work and moves matter
Mechanical Energy: Energy resulting from the position or movement of objects
Chemical Energy: Form of potential energy in the chemical bonds of a substance
Heat Energy: Energy that flows between objects of different temperatures

33. Energy and Chemical Reactions

34. Speed of Chemical Reactions
Activation Energy: Minimum energy reactants must have to start a chemical reaction
Catalysts: Substances that increase the rate of chemical reactions without being permanently changed or depleted
Enzymes: Increase the rate of chemical reactions by lowering the activation energy necessary for reaction to begin

35. Activation Energy and Enzymes

36. Cells: The Fundamental Units of Life
Cells are the basic structural and functional units of all forms of life.
Prokaryotic cells (bacteria) lack a distinct nucleus.
Eukaryotic cells (plants and animals) have a distinct nucleus.
Figure 2-6

37. Animation: Prokaryotic and Eukaryotic Cells
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38. Stepped Art Fig. 2-7, p. 38 A human body contains trillions
of cells, each with an identical
set of genes.
There is a nucleus inside each
human cell (except red blood cells).
Each cell nucleus has an identical
set of chromosomes, which are
found in pairs.
A specific pair of chromosomes
contains one chromosome from
each parent.
Each chromosome contains a long
DNA molecule in the form of a coiled
double helix.
Genes are segments of DNA on
chromosomes that contain instructions
to make proteins—the building blocks
of life.
The genes in each cell are coded
by sequences of nucleotides in
their DNA molecules.
Stepped Art
Fig. 2-7, p. 38

39. All Living Organisms are made up of Macromolecules:
Complex Carbohydrates
Proteins
Nucleic Acids
Lipids
Figure 2-7

40. States of Matter
The atoms, ions, and molecules that make up matter are found in three physical states:
solid, liquid, gaseous.
A fourth state, plasma, is a high energy mixture of positively charged ions and negatively charged electrons.
The sun and stars consist mostly of plasma.
Scientists have made artificial plasma (used in TV screens, gas discharge lasers, florescent light).

41. Matter Quality
Matter can be classified as having high or low quality depending on how useful it is to us as a resource.
High quality matter is concentrated and easily extracted.
low quality matter is more widely dispersed and more difficult to extract.
Figure 2-8

42. CHANGES IN MATTER
Matter can change from one physical form to another or change its chemical composition.
When a physical or chemical change occurs, no atoms are created or destroyed.
Law of conservation of matter.
Physical change maintains original chemical composition.
Chemical change involves a chemical reaction which changes the arrangement of the elements or compounds involved.
Chemical equations are used to represent the reaction.

43. Chemical Change
Energy is given off during the reaction as a product.

44. Types of Pollutants
Factors that determine the severity of a pollutant’s effects: chemical nature, concentration, and persistence.
Pollutants are classified based on their persistence:
Degradable pollutants
Biodegradable pollutants
Slowly degradable pollutants
Nondegradable pollutants

45. Nuclear Changes in Atoms
Natural radioactive decay: unstable isotopes spontaneously emit fast moving chunks of matter (alpha or beta particles), high-energy radiation (gamma rays), or both at a fixed rate.
Radiation is commonly used in energy production and medical applications.
The rate of decay is expressed as a half-life (the time needed for one-half of the nuclei to decay to form a different isotope).

46. Animation: Positron-Emission Tomography
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47. Animation: Half-Life
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48. Nuclear Changes: Fission
Nuclear fission: nuclei of certain isotopes with large mass numbers are split apart into lighter nuclei when struck by neutrons.
Figure 2-9

49. Stepped Art Fig. 2-6, p. 28 Uranium-235 Energy Fission fragment n
Neutron
Stepped Art
Fig. 2-6, p. 28

50. Nuclear Changes: Fusion
Nuclear fusion: two isotopes of light elements are forced together at extremely high temperatures until they fuse to form a heavier nucleus.
Figure 2-10

51. Video: Nuclear Energy
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VIDEO
From ABC News, Environmental Science in the Headlines, 2005 DVD.

52. ENERGY Energy is the ability to do work and transfer heat.
Kinetic energy – energy in motion
heat, electromagnetic radiation
Potential energy – stored for possible use
batteries, glucose molecules

53. Electromagnetic Spectrum
Many different forms of electromagnetic radiation exist, each having a different wavelength and energy content.
Figure 2-11

54. Electromagnetic Spectrum
Organisms vary in their ability to sense different parts of the spectrum.
Figure 2-12

55. Animation: Visible Light
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56. Source of Energy Energy Tasks Relative Energy Quality (usefulness)
Electricity
Very high temperature heat
(greater than 2,500°C)
Nuclear fission (uranium)
Nuclear fusion (deuterium)
Concentrated sunlight
High-velocity wind
Very high-temperature heat (greater than 2,500°C) for industrial processes and producing electricity to run electrical devices (lights, motors)
High-temperature heat
(1,000–2,500°C)
Hydrogen gas
Natural gas
Gasoline
Coal
Food
Mechanical motion to move
vehicles and other things)
High-temperature heat
(1,000–2,500°C) for
industrial processes and
producing electricity
Normal sunlight
Moderate-velocity wind
High-velocity water flow
Concentrated geothermal energy
Moderate-temperature heat
(100–1,000°C)
Wood and crop wastes
Moderate-temperature heat
(100–1,000°C) for
industrial processes, cooking, producing
steam, electricity, and
hot water
Figure 2.13
Natural capital: categories of the qualities of different sources of energy. High-quality energy is concentrated and has great ability to perform useful work. Low-quality energy is dispersed and has little ability to do useful work. To avoid unnecessary energy waste, you should match the quality of an energy source with the quality of energy needed to perform a task.
Dispersed geothermal energy
Low-temperature heat
(100°C or lower)
Low-temperature heat
(100°C or less) for
space heating
Fig. 2-13, p. 44

57. ENERGY LAWS: TWO RULES WE CANNOT BREAK
The first law of thermodynamics: we cannot create or destroy energy.
We can change energy from one form to another.
The second law of thermodynamics: energy quality always decreases.
When energy changes from one form to another, it is always degraded to a more dispersed form.
Energy efficiency is a measure of how much useful work is accomplished before it changes to its next form.

58. Mechanical energy (moving, thinking, living)
Chemical
energy
(photosynthesis)
Chemical
energy
(food)
Solar
energy
Waste
Heat
Waste
Heat
Waste
Heat
Waste
Heat
Figure 2.14
The second law of thermodynamics in action in living systems. Each time energy changes from one form to another, some of the initial input of high-quality energy is degraded, usually to low-quality heat that is dispersed into the environment.
Fig. 2-14, p. 45

59. SUSTAINABILITY AND MATTER AND ENERGY LAWS
Unsustainable High-Throughput Economies: Working in Straight Lines
Converts resources to goods in a manner that promotes waste and pollution.
Figure 2-15

60. Sustainable Low-Throughput Economies: Learning from Nature
Matter-Recycling-and-Reuse Economies: Working in Circles
Mimics nature by recycling and reusing, thus reducing pollutants and waste.
It is not sustainable for growing populations.

61. Sustainable low-waste economy Matter Feedback Energy Feedback Inputs
(from environment)
System
Throughputs
Outputs
(into environment)
Energy
conservation
Low-quality
Energy
(heat)
Energy
Sustainable
low-waste
economy
Waste
and
pollution
Waste
and
pollution
Pollution
control
Matter
Recycle
and
reuse
Figure 2.16
Solutions: lessons from nature. A low-throughput economy, based on energy flow and matter recycling, works with nature to reduce the throughput of matter and energy resources (items shown in green). This is done by (1) reusing and recycling most nonrenewable matter resources, (2) using renewable resources no faster than they are replenished, (3) using matter and energy resources efficiently, (4) reducing unnecessary consumption, (5) emphasizing pollution prevention and waste reduction, and (6) controlling population growth.
Matter
Feedback
Energy Feedback
Fig. 2-16, p. 47

62. Animation: Economic Types
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