Transcript STAAR Lesson Review

STAAR LESSON
REVIEW
TEKS 8.5F
recognize whether a chemical equation
containing coefficients is balanced or not and
how that relates to the law of conservation of
mass.
Guiding Question:
What happens to atoms in a chemical reaction?
CHEMICAL EQUATIONS
PRACTICE
TEKS 8.5F
Think/Pair/Share
1. What is a coefficient?
2. What is a subscript?
3. Give some examples of symbols of elements.
4. If an element has a coefficient of 5 and a subscript of 2,
how many atoms of that element are present?
(ex. 5H2 = 10 atoms of hydrogen)
Examine the Chemical Equations
In your handout…
•Label the reactant and product side.
•Look at all of the elements on the reactant side and count
the number of atoms for each element.
•Next, identify the same elements on the product side and
count the number of atoms for each element.
•If the two sides are not equal, the equation is NOT
balanced. Try to add coefficients in front of each compound
or element of the equation to make it balance.
Review Questions
Write/Share/Revise
1. What does --> mean?
2. What side of the equation are the reactants on?
3. What side of the equation are the products on?
4. What is the reasoning behind the subscripts not
changing when balancing a chemical equation?
5. Why is it important that both sides of the equation have
the same number of atoms of each element?
CHECKING FOR
UNDERSTANDING
TEKS 8.5F
JEFFERSON LAB
Balancing Act!
http://education.jlab.org/elementbalancing/index.html
8.5E Exit Ticket
Reactants
Products
1. How is the chemical equation related to the Law of Conservation of
Mass?
A
The chemical reaction is reversible
B
The chemical reaction is not reversible.
C
The number of molecules in the reactant is equal to the
number of molecules in the product.
D
The number of atoms of each element in the reactants is
equal to the number of atoms of each element in the product.
8.5E Exit Ticket
2. Which equation is correctly balanced?
A
B
C
D
2NaN3 → 3Na + 2N2
2NaN3 → Na + 3N2
2NaN3 → 2Na + N2
2NaN3 → 2Na + 3N2
8.5E Exit Ticket
3. Which of the following chemical equations is
balanced?
A. 2HClO
e
2H2O +
2Cl2O
B. CuO
+
2HCl e
2CuCl2
+
C. MgCl2
+
NaF e
MgF2 +
NaCl
D. 2C2H2
+
5O2 e
4CO2 +
2H2O
H2O