Download Word Equations • a summary

CHEMISTRY CHAPTER 6
Topic:
6.1 Word Equations
6.3 Conserving Mass
HOMEWORK page 232 # 1-6
Note:
Word Equations


a summary of a chemical reaction using words
shows the starting chemicals (reactants) and the new chemicals (products)
reactants ------> products
ex.
magnesium + vinegar -------> hydrogen + magnesium acetate
hydrogen + oxygen -------> water
Complete the following:
a) aluminum + __oxygen____ -----> aluminum oxide
b) zinc + oxygen ----> ___zinc oxide_____
c) aluminum + copper chloride ---> copper + __aluminum chloride____
d) sodium sulfate + calcium chloride ---> calcium sulfate + ___sodium chloride____
Conservation of Mass


The Law of Conservation of Mass – in a chemical reaction, the total mass of the
reactants is always equal to the total mass of the products
The number of each kind of atom does not change, the atoms are simply rearranged
Use molecular building kits to look at the reaction of:
Methane +
CH4
oxygen
+
O2
water + carbon dioxide
H2O +
CO2
Lesson/Topic:
6.5 Balancing Chemical Equations
Homework: worksheet and textbook page 236 # 1-7
Note:
Balancing Chemical Reactions
From two days ago, the conservation of mass states:
the total mass of the reactants = total mass of the products
Why?
In any chemical reaction, atoms are neither created nor destroyed, just
rearranged.
Therefore, because of the conservation of mass, chemical equations are balanced
when the number of each type of atom is the same on either side of the arrow sign.


Balanced Chemical Equation: an equation in which the reactants and the products
contain equal numbers of atoms of each type
Coefficients: a number written in front of a chemical symbol or formula which
indicates the number of atoms or molecules of that substance
How to Balance an Equation
1.
2.
3.
Count the number of atoms of each type in reactants and products (except O and
H), then balance
Count the number of atoms of O in reactants and products, then balance
Count the number of atoms of H in reactants and products, then balance
ex.
H2 + O2 ---->
H2O
ex.
Mg + O2 --->
MgO
ex.
Ca + CH3COOH --->
H2 + Ca(CH3COO)2
Lesson/ Topic:
6.7 Types of Chemical Reactions: Synthetic and Decomposition
Lesson:
Homework: p235 1-4
Note:
Types of Reactions

There are four major types of reactions and one sub-type
1. Synthesis Reactions
 Reactions which combine atoms and/or compounds into larger compounds.
 There are two or more reactants and only one product.
General formula: X + Y  XY
eg 1
H2 + O2  2 H2O
eg 2
MgO + H2O  Mg(OH)2
eg 3
HCl + NH3  NH4Cl
Try this…predict the product of this synthesis reaction:
Al + O2

Al2O3
2. Decomposition Reactions
 Opposite of synthesis reactions.
 Reactions where compounds breakdown into elements or smaller compounds.
 There is only one reactant and two or more products.
General formula: XY  X + Y
eg 1
H2O  H2 + O2
eg 2
KClO3  KCl + O2
(balance)
eg 3
NI3  N2 + I2
(balance)
(balance)
Try this…predict the product of this decomposition reaction:
Ag2O 
Ag +
O2
(balance this also)
Lesson/Topic:
6.10 Types of Reactions: Single and Double Displacement
Materials Needed:
Lesson:
Homework: p241 1-3
Note:
Types of Reactions
3. Single Displacement Reactions
 Reactions in which one element “displaces” or replaces another in a
compound.
 The general formula is an element reacting with a compound to produce a new
element and a new compound.
 A metal (cation) can displace another metal (cation) or hydrogen:
X + YZ  Y + XZ
eg. 1 Mg + ZnCl2  Zn + MgCl2
eg. 2 Mg + H2SO4  H2 + MgSO4
Try this…predict the product of this single displacement reaction:
Cu + AgNO3 

Cu(NO3)2 + Ag
(balance)
Another type of single displace reaction is where a nonmetal (anion) displaces
another nonmetal (anion)- basically, the anions switch places.
A2 + YB  B2 + YA
eg
Cl2 + NaBr  Br2 + NaCl
4. Double Displacement Reactions
 Reactions in which elements (or polyatomic ions) in different compounds
“displace” each other by changing places.
 The general formula is for two compounds to react to produce two new
compounds:
WX + YZ  WZ + YX
eg. 1 AgNO3 + KI  AgI + KNO3
eg. 2 Na2CO3 + CaCl2  NaCl + CaCO3
(balance)
eg. 3 HCl + NaOH  H2O + NaCl
eg. 4 H2SO4 + NaOH  H2O + Na2SO4
(balance)
Try this…predict the product of these double displacement reactions:
FeCl3 + NaOH 
Fe(OH)3 + NaCl
HNO3 + KOH 
H2O +
(balance)
KNO3
PUTTING IT ALL TOGETHER…please complete the VOYAGE through Equations
worksheet for added practice of these concepts and skills.