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Chemistry Alive: Review of Basic Concepts

Chemistry Alive: Review of Basic Concepts. It is soooooooo important that you understand so please ask questions. I will post this slides to my Brookwood teacher page today. www.brookwoodhighschool.net/tlu.php?type=F Select Crawford from drop down and go to handouts. Concepts of Matter.

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Chemistry Alive: Review of Basic Concepts

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  1. Chemistry Alive: Review of Basic Concepts • It is soooooooo important that you understand so please ask questions. • I will post this slides to my Brookwood teacher page today. • www.brookwoodhighschool.net/tlu.php?type=F • Select Crawford from drop down and go to handouts

  2. Concepts of Matter • Anything that occupies space and has mass • Mass remains constant but weight varies with gravity • Matter can be seen, smelled and/or felt • Solid, liquid or gas • Matter can be changed physically or chemically • Liquids conform to the shape of the container • Gas- no definite shape nor definite volume

  3. Matter is composed of substances called elements Elements cannot be broken down into simpler substances by ordinary chemical methods 96 % of body weight is made up of 4 elements Carbon, Oxygen, Hydrogen, Nitrogen Atoms are the building blocks of elements- identical particles Composition of Matter

  4. Pure substances like carbon, hydrogen and oxygen that are composed of only one type of atom are classified as elements. Element is designated by a one- or two- letter chemical shorthand called the atomic symbol, C is for Carbon, Na is for sodium Atom is derived from the Greek word meaning “incapable of being divided” If an atom is split into its sub particles it loses the unique properties of its element Elements and Atoms

  5. Elements of Life

  6. Trace elements less than 0.1 %: Cr, Co, Cu, Fl, Mn, Mo, Se, Si, Sn, V, Zn; Many found as part of enzymes or required for enzyme activation

  7. Molecular Substances When two or more atoms are chemically bonded a molecule is formed. Two atoms of the same element bond together an element is produced. I.e. O2, H2 Two or more different atoms form molecules of a compound, CH4 Molecule is the smallest part of a compound that retains the features of that compound

  8. Compounds • A compound is a substance made from two or more elements which have reacted chemically with each other. For example : The element sodium is a highly reactive metal and the element chlorine is a yellow-green poisonous gas (non-metal). When the two react together, they form a compound called sodium chloride. Sodium chloride is common salt, which you eat with food.

  9. Chemical Bonds • Ionic • Electron transferred • Covalent • Electron shared • Hydrogen (polar covalent) • Electron shared unequally

  10. Chemical Reactions reaction where reactants and products are balanced C6H12O6 + 6O2 6CO2 + 6H2O + ATP • When reactions take place, there is an exchange of energy. • Whenever chemical bonds are broken, energy is released. • When new bonds are formed, energy is stored. • Sometimes [when the energy stored in the new bonds of the products is less than the energy released from the reactants] energy is released during a reaction. This energy may be given off as heat, or it may be used to do work. • Sometimes, the products of the reaction store more energy in their chemical bonds than the reactants had stored. This stored energy can be held for later use.

  11. Chemical Reactions All chemical reactions involve atoms trying to get a full outer shell of electrons. When an atom reacts with another atom, it will either 1. Lose electrons to form a stable positive ion. 2. Gain electrons to form a stable negative ion. 3. Share electrons to form a stable molecule. Key to chemical reactivity is the rule of 8s. ( Octet Rule)

  12. Synthesis reactions As an example of a synthesis reaction : Ca + S -------------------> CaS The + sign means "reacts with" or "combines with" and the arrow indicates "to form".

  13. Synthesis Reactions: Summary • Involve bond formation • Energy-absorbing reactions • Underlie all anabolic (constructive) activities in body cells • Growth and repair of worn-out or damaged tissues

  14. Decomposition reactions An example of a decomposition reaction is : The products of this decomposition reaction have quite different chemical properties to the initial compound.

  15. Decomposition Reactions • Bonds are broken • Chemical energy is released • Catabolic (destructive) processes • Molecule-degrading reactions • Digestion of food into building blocks • Breakdown of glycogen to release glucose

  16. Exchange Reactions • Involves both synthesis and decomposition reactions • Bonds are both made and broken • ATP reacts with glucose forming glucosephosphate and ADP • AB + C AC + B • AB + CD AD +CB

  17. Chemical Reactions • If a reaction releases energy it is exergonic • If a reaction absorbs energy it is endergonic Catabolic and oxidative reactions are for the most part exergonic

  18. 4 Factors influencing chemical rxns • Temperature: An increase in temperature increases the kinetic energy therefore the reactions are quicker • Amount: As the concentration of reactants decline we reach chemical equilibrium • Size: Smaller particles move faster, hence faster reactions • Catalysts: increase a reaction without being used up, enzymes

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