Sci 4th Qtr

• Chemical Nomenclature

  The naming of compounds
• Chemical Formula


  The representation of the elements of a compound and the relative proportions of those elements
• Chemical Equation


  Representations of chemical reactions on paper
• Chemical Equation


  • 2H₂ + O₂ → 2H₂O
• Compound

  A substance composed of two or more elements wherein molecules are its smallest particle
• Molecule


  The smallest particle of a compound
• Chemical bond


  The force that holds atoms together in a molecule
• Cation


  An ion with a positive charge
• Anion


  An ion with a negative charge
• Ionic compound


  A compound that uses a metal cation and a nonmetal anion
• Covalent compound


  A compound where atoms share electrons
• Electropositive


  An element that is further left on the periodic table
• Electronegative


  An element that is further right on the periodic table
• Numerical prefixes


  Used to specify the number of atoms in a covalent molecule
• Physical change


  A change in the material that does not involve a change in its chemical composition
• Chemical change


  A change that involves the breaking and forming of chemical bonds, resulting in new substances
• Reactants


  The substances that initiate a chemical reaction
• Products


  The substances that result from a chemical reaction
• Chemical equation


  A representation of a chemical reaction showing the reactants and products
• Coefficients


  Numbers placed in front of molecules in a chemical equation to balance the equation
• Balanced equation


  A chemical equation where the number of atoms of each element is the same on both sides
• Law of conservation of mass


  The principle that matter is neither created nor destroyed in a chemical reaction
• Balancing a chemical equation


  Count the atoms on each side

  2. Change coefficients to balance atoms

  3. Do not change subscripts

  4. Count polyatomic ions as one item

  5. Ensure all atoms are counted
• Balancing by inspection


  Observing the quantities of atoms and adding coefficients to balance the equation
• Balancing by algebraic method


  Using algebraic variables as coefficients and solving equations to balance the equation
• Do not change subscripts of atoms when balancing chemical equations
• Count polyatomic ions as one item when balancing chemical equations
• Do not forget to count all the atoms since it is a common erroneous practice when balancing chemical equations
• Balancing by Inspection


  1. Observe the quantity of atoms present on each side of the equation

  2. Add coefficients to the molecules to balance the number of atoms
• Balancing by Algebraic Method


  1. Use algebraic variables as stoichiometric coefficients for each species

  2. Solve the mathematical equations to get each coefficient
• Balancing by Algebraic Method


  1. Write the equation as an algebraic expression

  2. Determine the equation for each chemical species

  3. List the equations by chemical species

  4. Assign a value to one variable

  5. Substitute the values to obtain the other variables
• Stoichiometric coefficients


  The total number of molecules of a chemical species present in a chemical reaction
• Combination or Synthesis Reaction


  The combination of two or more reactants to produce a single product
• Decomposition Reaction


  The breaking of a substance into two or more elements or compounds
• Single Replacement or Displacement Reaction


  An uncombined active element displaces another element in a compound and takes its place
• Double Replacement or Displacement Reaction

  Atoms or ions from two different compounds replace one another
• Combustion Reaction


  Compounds rapidly combine with oxygen gas producing carbon dioxide and water
• Periods and Groups in the Periodic Table
• Blocks in the Periodic Table
• Metals, Non-metals, and Metalloids in the Periodic Table