• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
Chemical equations 11
 

Chemical equations 11

on

  • 661 views

 

Statistics

Views

Total Views
661
Views on SlideShare
661
Embed Views
0

Actions

Likes
0
Downloads
15
Comments
0

0 Embeds 0

No embeds

Accessibility

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    Chemical equations 11 Chemical equations 11 Presentation Transcript

    • Chemical Equations
      • Putting chemical changes into words
      • When atoms are joined together, they form a
      • _____BOND______.
      • Atoms bond together for a very simple reason: atoms like to have full valence shells . (8 electrons)
      • Atoms will share, give away, or gain electrons when forming a bond.
      • Substances in which 2 or more elements have bonded together form a material with unique chemical properties.
      • Example : water - 2 Hydrogen atoms bonded to 1 Oxygen atom. H2O
    • All matter is made of atoms. Why would an atom combine with other atoms? To make the atom stable When an atom combines with another atom, this forms a molecule? The other type of bond is a compound.
    • Compound Molecules
      • A combination of two or more different elements (atoms)
      • Examples:
        • 1 Na atom + 1 Cl atom = the compound NaCl
        • 2 H atoms + 1 O atom = the compound H O
      • The examples above are compounds because the molecule is made out of different atoms.
      2
    • A chemical equation is a symbolic representation of a chemical reaction .
    • Equation Example : The burning of methane gas in oxygen is: CH 4 + 2 O 2 -> CO 2 + 2 H 2 O
    • Review: Element Symbols
      • All elements are represented by a 1 or 2 letter symbol
        • For example
          • C = Carbon
          • Ne = Neon
          • O = Oxygen
      • The symbols are shown on the periodic table
    • Chemical Formulas
      • Shows the elements & number of atoms of each element in a molecule
      • H 2 SO 4
        • Elements
          • Hydrogen; 2 atoms
          • Sulfur: 1 atom
          • Oxygen: 4 atoms
        • 7 atoms total
        • subscripts show the number of atoms of that particular symbol only (the symbol to its left)
      Subscript
    • Coefficients
      • A formula may begin with a number.
      • If there is no number, then “1” is understood to be in front of the formula.
        • This number is called the coefficient .
        • The coefficient represents the number of molecules of that compound or atom needed in the reaction.
        • For example:
          • 2H 2 SO 4 – 2 molecules of Sulfuric Acid
    • Coefficients
      • 2H 2 SO 4 – 2 molecules of Sulfuric Acid
        • A coefficient is distributed to ALL elements in a compound
          • 2 – H 2 (for a total of 4 H atoms)
          • 2 – S (for a total of 2 S atoms)
          • 2 – O 4 (for a total of 8 O atoms)
    • Reading Chemical Equations
      • Each side of an equation represents a combination of chemicals.
      • The combination is written as a set of chemical formulas, separated by + symbols.
        • CH 4 + 2 O 2 -> CO 2 + 2 H 2 O
      Coefficient
    • Reading Chemical Equations
      • The two sides of the equation are separated by an arrow.
        • The combination of chemicals before the reaction are on the left side of the arrow called reactants
        • The right side indicates the combination of chemicals after the reaction called products.
    • For Example :
      • In this reaction, sodium ( Na ) and oxygen ( O 2 ) react to make a single molecule, Na 2 O Label the reactants and products.
      Na + O 2 -> Na 2 O
    • Balancing Equations
      • The Law of Conservation of Mass states that in a chemical reaction, the quantity or amount of each element does not change .
      • This means that each side of the equation must represent the same quantity of each element ; in other words have the same number of each kind of atom.
    • Balancing Equations Na + O 2 -> Na 2 O
      • In order for this equation to be balanced , there must be equal amount of Na on the left hand side and on the right hand side. Right now, there is 1 Na atom on the left but 2 Na atoms on the right.