CHAPTER 9 CHEMICAL REACTIONS AND EQUATIONS - PowerPoint PPT Presentation

1 / 10
About This Presentation
Title:

CHAPTER 9 CHEMICAL REACTIONS AND EQUATIONS

Description:

Mass is conserved in chemical reactions. Mass of products = mass of reactants ... Note (diatomic elements are marked with a green X on the periodic chart at the ... – PowerPoint PPT presentation

Number of Views:408
Avg rating:3.0/5.0
Slides: 11
Provided by: nedhil
Category:

less

Transcript and Presenter's Notes

Title: CHAPTER 9 CHEMICAL REACTIONS AND EQUATIONS


1
CHAPTER 9 CHEMICAL REACTIONS AND EQUATIONS
2
Law of conservation of Matter
  • Mass is conserved in chemical reactions
  • Mass of products mass of reactants
  • 2H2 O2 ? 2H2O
  • 4 amu 32 amu 2 (18 amu)

3
The atoms of each element are also conserved.
  • 2H2 O2 ? 2H2O
  • 4 H atoms, 2 O atoms ? 4 H atoms and
    2 O atoms

4
BALANCING CHEMICAL EQUATIONS
  • When you are given an equation to balance the
    chemical formulas will be correct. DO NOT
    CHANGE THESE.
  • H2 O2 ? H2O
  • Note (diatomic elements are marked with a green X
    on the periodic chart at the front of the
    room.)
  • Balance equations by placing coefficients in
    front of the formulas.
  • Balance only one element (or polyatomic ion) at
    a time until the entire equation is balanced.

5
  • Complete balancing worksheet

6
CLASSIFYING CHEMICAL REACTIONS
  • Combination reaction (also called synthesis)
  • A B ? AB
  • Identified by two reactants only one product
  • Na Cl2 ? NaCl
  • CO2 H2O ? H2CO3

7
Decomposition Reaction
  • Exact opposite of combination reaction
  • One compound is broken down decomposed into
    two.
  • Often energy has to be added to make this
    happen.
  • AB ? A B
  • H2CO3 ? CO2 H2O

8
Single Replacement Reactions
  • One element kicks another element out of a
    compound and takes its place.
  • A BX ? AX B
  • A more reactive metal will replace a less
    reactive metal or hydrogen. (See metal
    activity series page 295)
  • A more reactive nonmetal will replace a
    less reactive nonmetal (compare
    electronegativity)

9
Double Replacement Reaction
  • Compounds with positive and negative groups
    exchange partners.
  • AX BY ? AY BX
  • CaCO3 HCl ? CaCl2 H2CO3
  • The 4 ions of the starting materials are all
    dissolved in water and no reaction will take
    place unless
  • A molecular compound is formed (like water)
  • A precipitate is formed (check the solubility of
    possible products)
  • A gas that leaves the solution is formed

10
When will a reaction not take place?
  • A metal will not react with a metal.
  • A noble gas will not react with anything.
  • A less reactive element will not replace
    a more reactive element.
Write a Comment
User Comments (0)
About PowerShow.com