Write & balance rxns
Upcoming SlideShare
Loading in...5
×
 

Write & balance rxns

on

  • 1,191 views

 

Statistics

Views

Total Views
1,191
Slideshare-icon Views on SlideShare
969
Embed Views
222

Actions

Likes
0
Downloads
8
Comments
0

5 Embeds 222

http://zehnerchemistry.blogspot.com 207
http://www.zehnerchemistry.blogspot.com 6
http://zehnerchemistry.blogspot.in 4
http://zehnerchemistry.blogspot.ca 4
http://zehnerchemistry.blogspot.co.uk 1

Accessibility

Categories

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

    Write & balance rxns Write & balance rxns Presentation Transcript

    • I. Intro to Reactions Chp 11: Chemical Reactions
    • A.Signs of a Chemical Reaction
      • Evolution of heat and light
      • Formation of a gas
      • Formation of a precipitate
      • Color change
    • B.Law of Conservation of Mass
      • mass is neither created nor destroyed in a chemical reaction
      4 H 2 O 4 H 2 O 4 g 32 g 36 g
      • total mass stays the same
      • atoms can only rearrange
    • C. Chemical Equations
      • A+B  C+D
      REACTANTS PRODUCTS
    • C. Chemical Equations
    • D. Writing Equations
      • Identify the substances involved.
      • Use symbols to show:
      2H 2 ( g ) + O 2 ( g )  2H 2 O( g )
        • How many? - coefficient
        • Of what? - chemical formula
        • In what state? - physical state
      • Remember the diatomic elements.
    • D. Writing Equations
      • Two atoms of aluminum react with three units of aqueous copper(II) chloride to produce three atoms of copper and two units of aqueous aluminum chloride.
      • How many?
      • Of what?
      • In what state?
      Al 2 ( s ) + 3 CuCl 2 ( aq )  3 Cu ( s ) + 2 AlCl 3 ( aq )
    • E. Describing Equations
      • Describing Coefficients :
        • individual atom = “atom”
        • covalent substance = “molecule”
        • ionic substance = “unit”
      3 molecules of carbon dioxide 2 atoms of magnesium 4 units of magnesium oxide 3CO 2  2Mg  4MgO 
    • E. Describing Equations
      • to produce
      • How many?
      • Of what?
      • In what state?
      Zn( s ) + 2HCl( aq )  ZnCl 2 ( aq ) + H 2 ( g ) One atom of solid zinc reacts with two molecules of aqueous hydrochloric acid one unit of aqueous zinc chloride and one molecule of hydrogen gas.
    • II. Balancing Equations Chp 11: – Chemical Reactions
    • A. Balancing Steps
      • 1. Write the unbalanced equation.
      • 2. Count atoms on each side.
      • 3. Add coefficients to make #s equal.
      • Coefficient  subscript = # of atoms
      • 4. Reduce coefficients to lowest possible ratio, if necessary.
      • 5. Double check atom balance!!!
    • B. Helpful Tips
      • Balance one element at a time.
      • Update ALL atom counts after adding a coefficient.
      • If an element appears more than once per side, balance it last.
      • Balance polyatomic ions as single units.
        • “1 SO 4 ” instead of “1 S” and “4 O”
    • C. Balancing Example
      • Aluminum and copper(II) chloride react to form copper and aluminum chloride.
      1 1 1 1 2 3 2  3  6   3 3 3 2 2  2  6 Al + CuCl 2  Cu + AlCl 3 Al Cu Cl