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Bell Work:. 1.) Get out a blank piece of notebook paper. 2.) Complete the worksheet you have received. 3.) Write Notes 2-6: Chemical Formulas and Balancing Chemical Equations on the top of your blank piece of paper. Homework : 1.) Begin work on Balancing Equations worksheet
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Bell Work: • 1.) Get out a blank piece of notebook paper. • 2.) Complete the worksheet you have received. • 3.) Write Notes 2-6: Chemical Formulas and Balancing Chemical Equations on the top of your blank piece of paper. Homework: 1.) Begin work on Balancing Equations worksheet 2.) Study for your final
Notes 2-6 Chemical Formulas & Balancing Chemical Equations
What is a Chemical Reaction? • When two or more substances react chemically to form something new. • A process that leads to the transformation of one set of chemical substances to another. • Chemical equations are used to graphically illustrate chemical reactions.
What is a molecule? • A molecule is defined as a group of at least two atoms in a definite arrangement held together by covalent chemical bonds. • It is the smallest whole piece of a substance. • A molecule may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O).
Chemical Formula or Molecular Formula • The molecule methane (chemical formula CH4)
Write This Down!Molecular Formula • H2O • Element symbol • Subscript number (number of atoms in the molecule.)
Write This Down!Structural Formula • They show the arrangement of the atoms within the molecules, which atoms are bonded to which, and whether single, double or triple bonds are present. • Structural formula of Water - H2O
What is a Chemical Equation? • A chemical equation consists of the chemical formulas of the reactants (the starting substances) and the chemical formula of the products • The two are separated by an arrow symbol → usually read as "yields“. • The formula for the burning of methane CH4 + 2 O2 CO2 + 2 H2O
Burning Methane is what you use to heat something with a gas stove…..we call it natural gas
Write This Down!Parts of a Chemical Equation Coefficient Subscript CH4 + 2O2 CO2 + 2H2O Reactants Yields Products methane + oxygen carbon dioxide + water
Write This Down!The Law of Conservation of Mass • States that mass (atoms) is neither created nor destroyed in any ordinary chemical reaction. • Therefore, the mass of the products in a chemical reaction must always equal the mass of the reactants. CH4 + 2 O2CO2 + 2 H2O • Equations must balance……..
Balanced? H2 + O2 H2O Fix this equation.
Balanced? P2 + O2 P2O5 Fix this equation.
Balanced? NH4NO2 N2 + H2O Fix this equation.
Balancing Equations • A good website for practice. • http://www.sciencegeek.net/Chemistry/taters/EquationBalancing.htm
KHAN Academy • http://www.khanacademy.org/science/chemistry/chemical-reactions-stoichiometry/v/balancing-chemical-equations