1. Chemical Equations & Conservation of Matter
2017

2. EQ: Why are coefficients important? (TOP RIGHT)
Title your page: Chemical Reactions
EQ: Why are coefficients important? (TOP RIGHT)

3. (Yields/Produce)
Chemical Reaction – a reaction in which one or more substances are changed to new substances.
Reactants – substances that are about to react (LEFT side of equation)
Products – new substances produced (RIGHT side of equation)
Law of Conservation of Mass – total starting mass of all reactants MUST equal the total final mass of all products (cannot create or destroy mass!)
Chemical Reactions
DRAW and LABEL this!

4. Chemical Equation – uses chemical formulas and symbols to describe a chemical reaction and the product it produces.
Chemical Reactions
SYMBOL
MEANING 
Yield/Produces
(aq)
Aqueous (solid dissolved in water +
Plus
 Heat
Reactants heated
(s)
Solid
 Light
Reactants exposed to light
(l)
Liquid
 Elec
Electric current applied to reactants
(g)
Gas

5. Chemical Reactions
Coefficients (REVIEW!) – number that represents the number of UNITS of each substance in a rxn (Reaction)
Subscripts (REVIEW!) – number that represents the number of ATOMS in a molecule of a particular element

6. Answer EQ: Why are coefficients important? (TOP LEFT)
Videos to Review: m/movies/29/189/ Chemical Reactions
m/movies/29/189/ Conservation of Matter
m/movies/29/189/ Reactants
Answer EQ: Why are coefficients important? (TOP LEFT)

7. EQ: Why do chemical equations need to be balanced? (TOP RIGHT)
Title your page: Balancing Chemical Equations
EQ: Why do chemical equations need to be balanced? (TOP RIGHT)

8. Balancing Chemical Equations
Balanced chemical equations – have the same number of atoms of each element on BOTH sides of equation
When balancing chemical equations NEVER change the SUBSCRIPTS (NO TOUCHY!), instead change the COEFFICIENT in FRONT of the compounds needing balance.
YES!!!
NO!!!

9. Balancing Chemical Equations
Steps to Balancing a Chemical Equation
STEP #1 – Write a chemical equation for the reaction using formulas and symbols – make sure REACTANTS are on the LEFT and PRODUCTS are on the RIGHT! (This will ALMOST ALWAYS be DONE for YOU!!)
STEP #2 – COUNT the ATOMS in reactants and products.
STEP #3 – Choose COEFFICIENTS that balance the equation.
HINT! Generally, if there is an EVEN number of an element on one side and an ODD on the other side, place a 2 in front of compound containing ODD number of atoms – then COUNT AGAIN!
STEP #4 – RECHECK the numbers of each ATOM on BOTH sides of equation & ADJUST coefficients if necessary
REMINDER – NEVER change SUBSCRIPTS!!

10. Balancing Chemical Equations
Let’s Work the Sample! Follow the STEPS!
___NaBr + ___ Cl2  ___NaCl + ___Br2
List the atoms…
Count the atoms…
Choose coefficients – remember the HINT!
Count & Recheck!

11. Balancing Chemical Equations
_2_NaBr + ___ Cl2  _2__NaCl + ___Br2
*Put a 2 in front of the ODD!
Recheck!
Na = 2 on BOTH sides
Br = 2 on BOTH sides
Cl = 2 on BOTH sides
Balancing Chemical Equations
Reactants
Products
Na = 1 need 2
Br = 1 need 2
Br = 2 ok
Cl = 2
Cl = 1 need 2

12. Answer EQ: Why do chemical equations need to be balanced? (TOP LEFT)
Videos to Review:
9/189/122 - Balancing Chemical EQ 1
9/189/123 - Balancing Chemical EQ 2
9/189/ Balancing Chemical EQ 3
9/189/124 - Balancing Chemical EQ 4
ulation/balancing-chemical- equations - Balancing Equations SIMULATOR!!
Answer EQ: Why do chemical equations need to be balanced? (TOP LEFT)