Transcript Welcome back to balancing equations!

BELL WORK: WELCOME BACK
1. Choose a new seat next to someone new in a new part
2.
3.
4.
5.
of the room.
What was the best part of your break that included an
ionic compound? (name the compound too)
What was the best part of your break that included a
covalent compound? (name the compound too)
Name a chemical change that you observed over the
break.
Which type of reaction was your break most like?
(synthesis, decomposition, single or double?) Why?
WELCOME BACK
TO CHEMISTRY!
We are going to review how to write
formulas and balance equations . . .
WE WILL STEP BY STEP, TRANSLATE A
SENTENCE INTO A BALANCED CHEMICAL
REACTION.
1. Copper (II) chloride reacts with aluminum foil to form aluminum
chloride and solid copper metal.
FIRST WE NEED FORMULAS. . . .
Copper (II) chloride
Step 1: Is the compound ionic or covalent?
Ionic
Step 2: What are the oxidation numbers?
Cu+2 and Cl-1
Step 3: Cross the charges to create a compound with a zero net charge.
CuCl2
Copper (II) chloride reacts with aluminum foil to form aluminum chloride and
solid copper metal.
WHAT’S THE FORMULA FOR ALUMINUM?
Al
What’s the formula for Aluminum Chloride?
Step 1: Is the compound ionic or covalent?
Ionic
Step 2: What are the oxidation numbers?
Al+3 and Cl-1
Step 3: Cross the charges to create a compound with a zero net charge.
AlCl3
Copper (II) chloride reacts with aluminum foil to form aluminum chloride and
solid copper metal.
WHAT’S THE FORMULA FOR COPPER?
Cu
Now we can write the equation:
CuCl2 + Al –> AlCl3 + Cu
What type of reaction is this?
There’s one more step . . . . . .
Copper (II) chloride reacts with aluminum foil to form aluminum
chloride and solid copper metal.
WE MUST HAVE A BALANCED EQUATION!
____ CuCl2+ ____ Al –> ____ AlCl3 + ____ Cu
Step 1: List elements or polyatomic ions under both
sides.
Cu
Cu
Cl
Cl
Al
Al
WE MUST HAVE A BALANCED EQUATION!
____ CuCl2+ ____ Al –> ____ AlCl3 + ____ Cu
Step 2: List how many of each are present in the
reaction.
Cu 1
Cu 1
Cl
2
Cl
3
Al
1
Al
1
WE MUST HAVE A BALANCED EQUATION!
____ CuCl2+ ____ Al –> ____ AlCl3 + ____ Cu
Step 3: Add numbers in front of compound as needed to
make the reactants equal the products.
Cu
1
Cu 1
Cl
2
Cl
3
Al
1
Al
1
What law does this step follow?
WE WILL STEP BY STEP, TRANSLATE A
SENTENCE INTO A BALANCED CHEMICAL
REACTION.
2. Lead Nitrate reacts with potassium iodide to form
potassium nitrate and a lead iodide precipitate.
FIRST WE NEED FORMULAS. . . .
Step 1: Is the compound ionic or covalent?
Step 2: What are the oxidation numbers?
Step 3: Cross the charges to create a compound with a zero net charge.
One point for each correct formula written in 4 minutes.
Lead Nitrate reacts with potassium iodide to form potassium nitrate and a
lead iodide precipitate.
WHAT TYPE OF REACTION IS THIS?
There’s one more step . . . . . .
Write out the unbalanced equation.
One point for type of reaction, one point for correct unbalanced equation
in 2 minutes.
WE MUST HAVE A BALANCED EQUATION!
_____Pb(NO3)2 +_____KI _____KNO3 + _____ PbI2
Step 1: List elements or polyatomic ions under both sides.
Step 2: List how many of each are present in the reaction.
Step 3: Add numbers in front of compound as needed to make
the reactants equal the products.
4 points for a correctly balanced equation in 4 minutes.
WE WILL STEP BY STEP, TRANSLATE A
SENTENCE INTO A BALANCED CHEMICAL
REACTION.
3. Hydrogen Peroxide (dihydrogen dioxide) breaks down
into oxygen gas and water.
FIRST WE NEED FORMULAS. . . .THEN AN
EQUATION.
Hydrogen Peroxide (dihydrogen dioxide)
breaks down into oxygen gas and water.
4 minutes:
One point for each correct formula written in
an unbalanced equation in.
One point for the type of reaction.
WE MUST HAVE A BALANCED EQUATION!
____ H2O2 → ____ H2O + ____ O2
4 points for a correctly balanced equation in 4 minutes.
CAN YOU DO IT ALL TOGETHER?
Calcium carbonate breaks down into calcium oxide
and carbon dioxide.
CAN YOU DO IT ALL?
Calcium carbonate breaks down into calcium oxide
and carbon dioxide.
8 minutes:
Correctly balanced equation ( 5 points)
Type of equation ( 2 points)
Which compound is covalent? ( 1 point)
A LITTLE DIFFERENT DIRECTION:
Solid calcium combines with oxygen gas in a
synthesis reaction.
5 minutes:
2 points for the correct product(s)
5 points for the correctly balanced equation
LAST ONE. . . .
Hydrochloric acid reacts with sodium
hydroxide to form sodium chloride and water.
8 minutes:
5 points for correctly balanced equation.
2 points for correct reaction type.
1 point for identifying the law that the reaction
follows.