A basic introduction to writing word equations in Middle School Chemistry.
Includes common reaction examples that can be easily replicated in the classroom.
A basic introduction to writing word equations in Middle School Chemistry.
Includes common reaction examples that can be easily replicated in the classroom.
1. 1/31/12 A/B Day
LEQ: What can happen to the reactants in a
chemical reaction?
1. What is the difference between a natural material
and a synthetic one?
2. Is steel natural or synthetic?
3. Is neon natural or synthetic?
4. A scientist is looking for evidence of a chemical
change. What is one thing he should look for?
5. A scientist is looking for evidence of a physical
change. What is one thing she should look for?
2. EOG Question:
Which of the following may happen during a
physical change?
A. New substances are formed
B. Reactants form products
C. A precipitate is formed
D. The temperature may increase
3. Let’s Review:
LAW OF CONSERVATION OF MATTER
Matter can’t be
_________ and it
can’t be
_____________.
4. Today’s LEQ: What can happen to the
reactants in a chemical reaction?
By the end of today, you should be able to…
1. Identify reactants and products
2. Apply the law of conservation of matter to
chemical reactions
3. Identify the creation of gases and precipitates
as a part of a chemical reaction
5. How many words can you make
using ONLY the letters below?
A A S P M E N R
U W T T G O B P
6. A A S P M E N R
U W T T G O B P
• Past • Brat
• West • Want
• Aspen • Poem
• Tram • Rap
• Pan • Part
• We • Sap
• Sat • Spent
• Men • Grant
12. DRAW THIS IN YOUR NOTES:
Chemical Reaction: process of forming
new substances (a chemical change!)
2H + O H 2O H O2
13. 2H + O H2O
+
Two One Water
Hydrogen Oxygen
Atoms Atom
14. DRAW THIS IN YOUR NOTES:
Chemical Reaction: process of forming
new substances (a chemical change!)
2H + O H 2O H O 2
1 Oxygen
2 Hydrogens 1 Water
15. EOG QUESTION:
Carbon combines with oxygen to form carbon
dioxide. What is the word equation for this
chemical reaction?
a. carbon dioxide carbon + oxygen
b. carbon carbon dioxide + oxygen
c. carbon + oxygen carbon dioxide
d. carbon dioxide + oxygen carbon
16. DRAW THIS IN YOUR NOTES:
Chemical Reaction: process of forming
new substances (a chemical change!)
Reactants Product
2H + O H 2O H O 2
1 Oxygen
2 Hydrogens 1 Water
17. Big Numbers vs. Little Numbers
H2O 6 H2O
ONE WATER 6 WATER
MOLECULE MOLECULES
-12 hydrogens,
-2 hydrogens
-6 oxygens
-1 oxygen
18. Big Numbers vs. Little Numbers
Reactants Products
6 CO2 + 6 H2O C6H12O6 + 6 O2
6 Carbon 6 Waters 1 Glucose 6 Oxygen
Dioxides particles
26. EOG QUESTION:
If the mass of the reactants in a chemical
reaction is 123.49 grams, what is the mass
of the products?
a. 78.49 grams
b. 123.49 grams
c. 246.98 grams
d. impossible to tell
27. 1. 2 H₂0 ₂ 2 H ₂ 0 + O ₂
12 g _____?_____
2. C3H8 + 5 O2 4 H2O + 3 CO2
4 .5 g + 3.5 g _______?_______
3. 4 Al + 3 O2 2 Al2O3
10 g + _?_ 18 g
4. 6 CO₂ + 6 H₂OC₆H₁₂O₆ + 6 O₂
75g + 45 g 10g + __?__
28. EOG QUESTION:
Chemical X has a mass of 5 grams, and chemical Y has
a mass of 10 grams. If the two chemicals are mixed
and a complete chemical reaction takes place, what is
most likely the mass of the product?
a. 5 grams
b. 10 grams
c. 15 grams
d. 50 grams
29. How is this possible with the law of
conservation of matter?
Reactants Products
32. Chemical Reactions
Law of Conservation of Matter
Mass of reactants -chemical
ALWAYS EQUALS reactions
the mass of the can
products! sometimes
Ex: form a
Reactants = 12 g
GAS!
Products = 12 g
33. EOG QUESTION:
After a chemical reaction occurs in an open test
tube, measurements indicate that the mass of the
reactants is greater than the mass of the products
remaining in the test tube. What most likely explains
the measurements?
a. a gas was produced
b. a solid was produced
c. the salinity of the reactants was high
d. the temperature of the reactants was low
34. What in the world is a precipitate?
• http://www.youtube.com/watc
h?v=RE-
dFN7U91M&feature=related
• http://www.youtube.com/watc
h?v=pFovlKpPCbI
• http://www.youtube.com/watc
h?v=Trdyqmzu3JA&feature=rel
ated
35. Chemical Reactions
Law of Conservation of Matter
Mass of reactants -chemical -chemical
ALWAYS EQUALS reactions reactions
the mass of the can can also
products! sometimes form a
Ex: form a PRECIPITATE!
Reactants = 12 g
GAS! (a solid that
Products = 12 g forms in a
solution)
37. Summarizer:
Consider the following: 2 S2O3 + I2 → S4O6 + 2I
1.What are the reactants?
2.What are the products?
3.If there are 12 grams of reactants in a chemical
reaction, what is the mass of the products?
4.If you create a chemical reaction in an open test
tube and the mass of the reactants is MORE than
the mass of the products, what happened?!
5.What is a precipitate?