CHEMISTRY
November 10, 2011
Brain Teaser

Identify the type of reaction:
+ O2  H2O
 CaSO4 + KOH  Ca(OH) 2 + K2SO4
 KClO3  KCl + O2
 AgNO3 + Cu  Cu(NO3) 2 + Ag
 H2

Write the chemical equation:
 Magnesium
reacts with chlorine gas in the air to form
magnesium chloride
Agenda





Brain Teaser
Review Types of Reactions
Notes: Balancing Equation
Cool Chemical Reactions Mini-Lab
Homework
 Complete
Reaction Types Worksheet 1
 Balance Equations in Lab Packet
Review

4 Types of Chemical Reactions
A + B  AB (1 product)
 Decomposition: (1 reactant) AB  A + B
 Single replacement: X + AB  XB + A
 Double replacement: AB + XY  AY + XB
 Synthesis:
Balancing Equation
Word Equations
 Describes a chemical reaction that occurs using the
names of the chemicals involved.
 Reactants versus Products
 An arrow is written between the reactants and products
to indicate that chemical change is occurring
 For
example: 2H2 + O2  2H2O
Balancing Equation

Atoms involved in a chemical reaction must be balanced.
 Same
number of atoms of each element on both sides of a
chemical equation.

Unbalanced equation
 Balance
the equation by adding coefficients in front of the
compounds
 Coefficients:
number of molecules of a particular compound
 Subscripts: number of atoms of each element in the compound
Balancing Equation
A.
B.
C.
Write the word equation
Write the CORRECT formula for all reactants and products
Balance the equation by using coefficients
1.
2.
3.
4.
5.
6.
7.
NEVER change the subscripts in the formula to balance the
equation
Elements need to be balanced from either side of the equation
Start with the first element and work right of the equation
Balance the number of oxygen and hydrogen atoms after all the
other elements have been balanced.
Go back and double check that all elements are balanced
BOX your coefficients when finished
USE PENCIL only!
Balancing Equation


Inspection Method
Algebraic Method
Balancing Equation

Inspection Method

Aluminum reacts with oxygen to produce aluminum oxide
 Chlorine
reacts with lithium bromide to produce lithium
chloride and bromine gas
Balancing Equation

Algebraic Method
 Aluminum
oxide reacts with sodium phosphate to produce
aluminum phosphate and sodium oxide
 Hydrogen
gas and nitrogen monoxide react to form water
and nitrogen gas
Practice Problems

___Ca(CN)2 + __AlF3  __CaF2 + ___Al(CN)3

Potassium phosphate + Calcium hydroxide  Calcium phosphate + Potassium hydroxide
Balancing Chemical Equations

Refer to Practice Worksheet
Cool Chemical Reactions

Objectives:




Write 4 chemical equations to explain the chemical reactions
Balance the equations
Record qualitative observations
Procedures:



Read each procedure carefully before beginning. Goggles are
required!
Restore Station Before Switching
DO NOT dump any chemicals down the sink



Waste  Waste Container
DO NOT cross contaminate chemicals
Burning Split Test



Oxygen Gas
Carbon Dioxide Gas
Hydrogen Gas 
Cool Chemical Reactions

Station 1: The Sparkler
 Hold

Mg strip with tongs and ignite with Bunsen burner
Station 2: The Fire Extinguisher
 Place
1 little scoop of sodium bicarbonate (2 cm deep) into a
test tube
 Add drops of HCl slowly into the test tube (fizz)
 Have a burning splint ready to test for the gas produced
 Discard solution into the sink and was clean test tube
Cool Chemical Reactions

Station 3: Spy Writing
 Dip
one end of Q-tip in lead (II) nitrate
 Draw and Let it Dry
 Dip other end of Q-tip in potassium iodide
 Wipe over writing. Let it dry
 Dipose Q-tip in Waste Container. Wash your hands!
 DO NOT TOUCH the chemicals on the paper!
Cool Chemical Reactions

Station 4: Hear it Pop
 Add
a piece of Mg ribbon into a test tube
 Add 1 pipette full of 3M hydrochloric acid
 Immediately place a stopper on the test tube to collect
the gas produced
 Have a burning splint ready to test for the gas
produced. Remove the stopper and test for gas
 DO NOT submerge splint into the liquid (DEMO)
 Discard content into Waste Beaker
Cool Chemical Reactions



A. Procedure (NEED TO WEAR GOGGLES!)
B. Observations: Refer to Handout
C. Write the chemical equation and BALANCE!
 Don’t

forget Cl2, I2, F2, Br2, O2, H2, N2
D. Refer to the handout
Cool Chemical Reactions
Lab Report
Refer to Rubric