Launch: 12/14Grab your binder and immediately take a seat!

Place binder paper and a pen/pencil on your desk.

Review Objective #1: I can write balanced chemical equations.

Tonight’s HW: Finish Review Worksheet #1

Launch 12/14

Launch 12/1416.How many grams does 2 moles of soda niter

NaNO3 weigh?

a. 17g

b. 85g

c. 170g

d. 1700g

Launch Answers

Launch Answers16.How many grams does 2 moles of soda niter

NaNO3 weigh?

a. 17g

b. 85g

c. 170g

d. 1700g

Practice Exam Results: B1Our goal = 80%

Our average = 86%

Questions dropped5, 6, 7, 9, 14

Practice Exam Results: B1Our goal = 80%

Our average = 78%

Questions dropped5, 6, 7, 9, 14

Practice Exam Results: B1Our goal = 80%

Our average = 87%

Questions dropped5, 6, 7, 9, 14

Practice Exam Results: B1Our goal = 80%

Our average = 88%

Questions dropped5, 6, 7, 9, 14

AnnouncementsUnit #5 Exam on Thursday

3 days to reviewAsk questions!No copying HW or classwork!

Make-up work is due on Wednesday

Binder check this week

Exam Information30 multiple-choice questions

Balancing equations (6 questions = 20%)The mole (9 questions = 30%)Conversions (15 questions = 50%)

gram mole (6 questions)gram atoms (3 questions)gram gram (6 questions)

3 free response

Review:Balancing Equations

Mr. Heffner12/14/09

CH4 + 2O2 CO2 + 2H2O

What’s a chemical equation?

Reactants Products“turn into”

What’s a chemical equation?

4Fe2(CO3)3

Multiply!8 X Fe12 X C36 X O

CoefficientSubscript

How are equations balanced?

There is a 3-step process for balancing equations:

1.Count the atoms on both sides

2.Change a coefficient & multiply out

3.Check tally (and repeat)

Rule: You can’t change the subscripts!

ExampleBalance the equation,

N2 + H2 NH3

Step #1: Count the atoms on both sides

N2 + H2 NH3

Example

2 X N 2 X H 1 X N3 X H

Unbalanced!

Step #2: Change coefficient & multiply out

N2 + H2 NH3

Example

2 X N 2 X H 1 X N3 X H

2

2 X N6 X H

2X( )

Step #3: Check tally (and repeat)

N2 + H2 NH3

Example

2 X N 2 X H

2

2 X N6 X H

3

6 X H

Still unbalanced!

3X( )

Step #3: Check tally (and repeat)

N2 + H2 NH3

Example

6 X H

2

2 X N6 X H

3

2 X N

Balanced!

Snowman ChallengeDirections:

Send one group member to pick a cardWrite down the equation and #Balance it showing all work (count, coefficient, check)When finished, send one group member to have me

check your answer

Rules: If you pick it, solve itOnly one card at a timeShow your work!Work together

Exit SlipHC2H3O2 + NaHCO3 NaC2H3O2 + H2CO3

� Which of the following correctly identifies all of the reactants in the above chemical equation.� NaC2H3O2

� NaHCO3

� NaC2H3O2 and HC2H3O2

� HC2H3O2 and NaHCO3

Exit Slip2. How many C atoms are there in 3C2H4?

a. 2

b. 3

c. 5

d. 6

Exit SlipH2 + Cl2 HCl

3. Is the above equation balanced?a. No, because H2 has a coefficient of 2.

b. No, because the number of Cl and H atoms are not equal on both sides of the equation.

c. Yes, because the number of H atoms is not equal on both sides.

d. Yes, because there are equal numbers of atoms on both sides of the equation.

Exit Slip4. Which of the following is a balanced equation

for the combustion of ethanol (C2H6O)?

a. C2H5OH + 3O2 CO2 + 2H2O

b. C2H5OH + 3O2 2CO2 + 3H2O

c. C2H5OH + O2 2CO2 + 3H2O

d. C2H5OH + 2O2 3CO2 + 2H2O

Exit Slip__C2H2 + __H2 __CH4

5. When the equation above is completely balanced, the coefficient for H2 would be

a. 1b. 2c. 3d. 4

HomeworkFinish practice questions worksheet