As a result of activities in grades 9-12, all students should d
US National Science Education Standards for Principles of Alchemy (Chemistry) www.synapses.co.uk/alchemy
As a result of activities in grades 9-12, all students should develop .
Abilities necessary to do scientific inquiry
Matter is made of minute particles called atoms, and atoms are composed of even
smaller components. These components have measurable properties, such as mass and electrical charge. Each atom has a positively charged nucleus surrounded by negatively charged electrons. The electric force between the nucleus and electrons holds the atom together. •
The atom's nucleus is composed of protons and neutrons, which are much more
massive than electrons. When an element has atoms that differ in the number of neutrons, these atoms are called different isotopes of the element. •
The nuclear forces that hold the nucleus of an atom together, at nuclear distances,
are usually stronger than the electric forces that would make it fly apart. Nuclear reactions convert a fraction of the mass of interacting particles into energy, and they can release much greater amounts of energy than atomic interactions. Fusion is the joining of two nuclei at extremely high temperature and pressure, and is the process responsible for the energy of the sun and other stars. •
Radioactive isotopes are unstable and undergo spontaneous nuclear reactions,
emitting particles and/or wavelike radiation. The decay of any one nucleus cannot be predicted, but a large group of identical nuclei decay at a predictable rate. This predictability can be used to estimate the age of materials that contain radioactive isotopes.
Atoms interact with one another by transferring or sharing electrons that are
furthest from the nucleus. These outer electrons govern the chemical properties of the element. •
An element is composed of a single type of atom. When elements are listed in
order according to the number of protons (called the atomic number), repeating patterns of physical and chemical properties identify families of elements with similar properties. This "Periodic Table" is a consequence of the repeating pattern of outermost electrons and their permitted energies. •
Bonds between atoms are created when electrons are paired up by being
transferred or shared. A substance composed of a single kind of atom is called an element. The atoms may be bonded together into molecules or crystalline solids. A compound is formed when two or more kinds of atoms bind together chemically. •
The physical properties of compounds reflect the nature of the interactions among
its molecules. These interactions are determined by the structure of the molecule, including the constituent atoms and the distances and angles between them. Principles of Alchemy (Chemistry) by Dr Jamie Love from Merlin Science
Solids, liquids, and gases differ in the distances and angles between molecules or
atoms and therefore the energy that binds them together. In solids the structure is nearly rigid; in liquids molecules or atoms move around each other but do not move apart; and in gases molecules or atoms move almost independently of each other and are mostly far apart. •
Carbon atoms can bond to one another in chains, rings, and branching networks to
form a variety of structures, including synthetic polymers, oils, and the large molecules essential to life.
Chemical reactions occur all around us, for example in health care, cooking,
cosmetics, and automobiles. Complex chemical reactions involving carbon-based molecules take place constantly in every cell in our bodies. •
Chemical reactions may release or consume energy. Some reactions such as the
burning of fossil fuels release large amounts of energy by losing heat and by emitting light. Light can initiate many chemical reactions such as photosynthesis and the evolution of urban smog. •
A large number of important reactions involve the transfer of either electrons
(oxidation/reduction reactions) or hydrogen ions (acid/base reactions) between reacting ions, molecules, or atoms. In other reactions, chemical bonds are broken by heat or light to form very reactive radicals with electrons ready to form new bonds. Radical reactions control many processes such as the presence of ozone and greenhouse gases in the atmosphere, burning and processing of fossil fuels, the formation of polymers, and explosions. •
Chemical reaction rates depend on how often the reacting atoms and molecules
encounter one another, on the temperature, and on the properties--including shape--of the reacting species. •
Catalysts, such as metal surfaces, accelerate chemical reactions. Chemical
reactions in living systems are catalyzed by protein molecules called enzymes.
CONSERVATION OF ENERGY AND INCREASE IN DISORDER•
The total energy of the universe is constant. Energy can be transferred by
collisions in chemical and nuclear reactions, by light waves and other radiations, and in many other ways. However, it can never be destroyed. As these transfers occur, the matter involved becomes steadily less ordered. •
Heat consists of random motion and the vibrations of atoms, molecules, and ions.
The higher the temperature, the greater the atomic or molecular motion. •
Everything tends to become less organized and less orderly over time.
The two missing sections of Physical Science -CONTENT STANDARD B (INTERACTIONS OF ENERGY AND MATTER and MOTIONS AND FORCES) are only briefly mentioned in “Principles of Alchemy (Chemistry)” because they are covered in detail in “Principles of Astronomy”. Principles of Alchemy (Chemistry) by Dr Jamie Love from Merlin Science
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