Chemical Reactions Part B
Packet #1
Ms. Rabenda
Name:__________________________Per: ___
Conservation of Matter Notes
•
Chemical Reactions
–
Happen all of the time
–
Happen naturally or can be man made
–
Can be physical or chemical
•
Law of Conservation of Matter
• Matter cannot be ______________or ________________!
• The total amount of matter remains __________________.
• Even though the matter may change from one form to another, the
same number of atoms exists before and after the change takes place!
• The mass of the ____________must equal the mass of the
____________.
•
Evidence
• The elements on the reactant side = the elements on the products
• The # of each element on the reactant side = the # of each element on the product
side
• The mass of the reactants = the mass of the products
• Example: Tin Fluoride
Tin + hydrogen fluoride → tin fluoride + hydrogen
What’s the total mass of the reactants?
•
So what should the mass of the products be?
2.01 g
156.71
g
•
Conservation Lab
“You can’t get something from nothing”
Background:
• The conservation of mass tells us that you cannot destroy or create matter. In this lab I
want you to prove it!
Materials:
•
1 zip lock bag
• 2 small plastic cups
• vinegar (acetic acid)
• baking soda (sodium bicarbonate)
• beakers
•
balance
Data:
Initial Mass (g)
Final Mass (g)
Change in mass (g)
(Final mass – Initial
mass)
Plastic Bag
Beaker
Plastic Bag Procedure:
1. Place 2 g of baking soda into a small plastic cup.
2. Place 10 mL of vinegar into a small plastic cup.
3. Put both cups in the plastic bag. Take care NOT to spill the contents of either cup.
4. Seal the plastic bag.
5. Determine the mass of the cups and their contents, and the plastic bag. Write the values in
your data table.
6. Without opening the bag, pour the vinegar into the cup of baking soda.
7. Observe
8. Without opening the bag, record the mass of the contents of the plastic bag. Take care not to
break the seal of the plastic bag.
Beaker Procedure:
1. Place 2 beakers on the balance
2. Press zero
3. Measure 2 g of baking soda in the smaller beaker (50 mL)
4. Pour 20 mL of vinegar into the larger beaker (100 mL)
5. Write your mass in your data table.
6. Without spilling, pour the baking soda into the vinegar
7. Observe
8. Record the mass of the contents of the beakers. (Both beakers should stay on balance)
Analysis Questions:
1.
What is a chemical reaction?
2.
Describe what happens when the vinegar was poured into the cup of baking soda.
3.
Is this a chemical reaction? What evidence do you have to support your answer?
4.
The gas produced in this reaction can put out fires. It is also a gas used by plants. Make
an educated guess about its identity.
5.
How does the change of mass from the plastic bag relate to the change of mass from
the beaker?
6.
Why do you think the changes in mass are different?
7.
What is the conservation of mass?
8. Which set up (plastic bag or beaker) demonstrates the conservation of mass more
accurately?
9. What experimental errors are associated with this lab? List at least 3.
•
•
•
Identifying Equation Components
1. Complete the table below.
Equations
H2 + O2  H2O
H2O2  H20 + O2
Na + O2  Na2O
N2 + H2  NH3
P4 + O2  P4O10
Fe + H2O  Fe3O4 + H2
C + H2  CH4
Na2SO4 + CaCl2 
CaSO4 + NaCl
C2H6 + O2  CO2 + H2O
Al2O3  Al + O2
Reactants
Products
Counting Atoms Notes
Writing Compounds
● Coefficient
● Number _____________the element/compound.
● Tells you how many of the _____________________ there are.
● Applies to everything after the coefficient up until the + or →
○ Example: 2H2O = The 2 coefficient is distributed to the H2 and the O
■ Total = 4 Hydrogen (2 x 2 = 4) and 2 Oxygen (2 x 1 = 2)
● Subscript
○ Number_________ the element - lower right side
○ Tells you how many _______________ of that element there are
○ Example: H2O → The 2 subscript only applies to the Hydrogen and not the
Oxygen.
○ Subscripts and parenthesis
■ If a subscript is after a parenthesis “( )” then it applies to everything
inside of it
■ Example: (H2O)2 = The 2 subscript applies to the H2O
■ Total = 4 Hydrogen (2 x 2 = 4) and 2 Oxygen (2 x 1 = 2)
●
Counting Atoms in a Compound Practice
○ CaCO3
■ Ca = 1
■ C=1
■ O=3
○ C9H8O4
■ C=
■ H=
■ O=
○ Mg(OH)2
■ Mg =
■ O=
■ H=
○ 2FeS2
■ Fe =
■ S=
○ H2O + O2
■ H=
■ O=
○ 2C7H5(NO2)3
■ C=
■ H=
■ N=
■ O=
Counting Atoms Worksheet
List the number of atoms of each element within the compound below.
C=2
O=4
Compound
Atoms in Compound
NaCl
Na = 1
Cl = 1
BaCl2
Ba =
Cl =
LiBr
Li =
Br =
FeS2
Fe =
S=
BaSO4
Ba =
S=
O=
CaSO4
Ca =
S=
O=
3CaCO2
Ca =
C=
O=
C6H4Cl2
C=
H=
Cl =
C2H4O2
C=
H=
O=
Mg(OH)2
Mg =
O=
H=
C7H5(NO2)3
C=
H=
N=
O=
2 Ca(H2PO4)2
Ca =
H=
P=
O=
2HBr
H=
Br =
3H20
H=
O=
2C202
C=
O=
Balancing Equation Notes
•
•
•
•
Why do we need to be balanced?
– All atoms that are on the _______________ are also on the ________________.
• Remember the Conservation of Mass Law
Steps to balancing Equations
1. Count the # of atoms on each side
2. Add Coefficients where necessary
● NEVER CHANGE OR ADD SUBSCRIPTS!
3. Recount the # of atoms on each side
4. Continue adding coefficients until the number of atoms on each side are equal.
5. Reduce the coefficient to the lowest terms (Hint: Start with 2 and see where it
gets you!)
Hints to Remember
– Order for Balancing
• _______________________
• Metals
• Ions
• Non-Metals
• Oxygen
• Hydrogen
• Balance Oxygen and Hydrogen LAST!
Step 1: Count the # of atoms of each side.
Step 2: Add Coefficients where necessary
•
Step 3: Recount the # of atoms on each side
•
Step 4: Continue adding coefficients until the number of atoms on each side are equal.

Practice Balancing Equations
___ Na + ___ Cl2 →___ NaCl
•
Additional Practice
• ___ CH4 + ___ O2 → ___ CO2 + ___ H2O
• ___ Li + ___ HNO3 → ___ LiNO3 + ___ H2
•
___ AgNO3+ ___ Cu → ___ Cu(NO3)2 + ___ Ag
• ___ Al + ___ O2 → ___ Al2O3
Balancing Equations Worksheet
Balance the following below:
1. ____Na + ____ MgF2
2. ____Mg + ____ HCl
3. ____Cl2 + ____ KI
→
_____ NaF + _____ Mg
→ _____ MgCl2 + _____ H2
→ ____ KCl + ____ I2
4. ____ HNO3 + ____ Mg(OH)2 → ____ H2O + ____ Mg(NO3)2
5. ____ H3PO4 + ____ NaBr → ____ HBr + ____ Na3PO4
6. ____ Na + ____ O2 → ____ Na2O
7. ____ C + ____ H2 → ____ C3H8
8. ____ Fe2O3 + ____ H2O → ____ Fe(OH)3
9. ____ C2H2 + ____ H2 → ____ C2H6
10.
____ CuSO4 + ____ NaOH → ____ Cu(OH)2 + ____ Na2SO4
11.
____ CF4 + ____ Br2 → ____ CBr4 + ____ F2
12.
____ Hg2I2 + ____ O2 → ____ Hg2O + ____ I2
13.
____ C7H16 +____ O2 →____ CO2 + ____ H2O