Conservation of Mass &
Chemical Reactions
09.20 & 09.21 2012 Ms. Boon Chemistry
Catalyst
Please take out your homework. You will need it in
order to do today’s lab.
Catalyst: The molecular formula of baking soda
(sodium hydrogen carbonate) is NaHCO3 .
1.
Name the four elements that make up this molecule.
2. State how many atoms of each element are in the
molecule.
3. List the molar mass of each element.
Objective
I can explain the law of
conservation of mass based on my
laboratory observations and data.
Agenda
Catalyst (10 min) & Debrief (5 min)
Introduction to Chemical Reactions (15 min)
Conservation Blows it Up! Lab
Demonstration and Instructions (15 min)
Conducting Laboratory Experiment (30 min)
Lab Write Up (30 min)
Exit Slip: Complete Lab Write Up
Introduction to Chemical Reactions
What is a chemical reaction?
http://www.youtube.com/watch?v=66kuhJkQCVM
Video Focus Questions: The video shows the
chemical reaction of iron and oxygen:
4 Fe (s) + 3 O2 (g) 
2 Fe2O3 (s)
1. What was the difference between the two reactions?
Why was there a difference?
Answer: The second reaction created more light/heat
energy because there was more oxygen available.
Introduction to Chemical Reactions
What is a chemical reaction?
A chemical reaction is a process in which one or more
substances change into one or more new substances.
The chemical properties and physical properties of
the new substances are different from those of the
original substances.
In a chemical reaction, the original substances, which
can be elements or compounds, are known as
reactants. The substances created are called
products.
3. What is a chemical equation?
(answer on pp. 263)
A chemical equation shows the chemical formulas and relative
amounts of all the reactants and products that are part of a
certain chemical reaction.
sodium hydrogen bicarbonate + acetic acid  sodium acetate +
carbon dioxide + water
NaHCO3 (s) + HC2H3O2 (aq) NaC2H3O2 (aq) + CO2 (g) + H2O (l)
Reactants
Products
Balanced Chemical
Equations
A chemical equation is “balanced” when there are the same
number of atoms of each element on both sides of the arrow.
NaHCO3 (s) + HC2H3O2 (aq) NaC2H3O2 (aq) + CO2 (g) + H2O (l)
Is it balanced?
Reactants
Products
Na = 1
Na = 1
H=5
H=5
C=3
C=3
O=5
O=5
Conservation Blows it
Up!
Please read the Lab introduction & Purpose silently (3
min)
Summarize the Introduction and Purpose to your
partner.
Please read the materials & procedure silently (3 min)
We will go over the materials and procedure
together. Ms. Boon will demonstrate some of the
steps.
Agenda
Catalyst (10 min) & Debrief (5 min)
Introduction to Chemical Reactions (15 min)
Conservation Blows it Up! Lab
Demonstration and Instructions (15 min)
Conducting Laboratory Experiment (30 min)
Lab Write Up (30 min)
Exit Slip: Complete Lab Write Up
Homework
Read pp. 267 – 270
Do problems: p. 269 #1-4.
Answers on Pp. 275-285: Vocabulary! Write down the
definitions and an example of the following:
Combustion reaction
Synthesis reaction
Decomposition reaction
Displacement reaction