Balancing Chemical Equations

Objectives: Students will...

explain what chemists mean when they say an equation is balanced.
balance chemical equations.

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How are you doing today?

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What was the highlight of your weekend?

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Examine the following reaction, then identify the reactants and products:
H₂O₂ --> H₂O + O₂

H₂O₂
H₂O
O₂

Reactant(s)
Product(s)

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Compare and contrast reactants and products in a chemical reaction.

Part 1: PhET Simulation

To start investigating how to balance chemical equations, spend a few minutes playing with the 'Introduction' screen in the simulation below. Make sure to check out the tools and figure out what they do.

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What does the smiley face in the simulation indicate?

A metal is somewhere in the reaction

A synthesis reaction occurred

The equation is balanced

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Balance the 'Make Ammonia' reaction. How many total molecules are on the reactants and products side?

Reactants: 3 molecules; Products: 2 molecules

Reactants: 4 molecules; Products: 2 molecules

Reactants: 2 molecules; Products: 1 molecule

Reactants: 8 molecules; Products: 8 molecules

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Balance the 'Make Ammonia' reaction. How many total atoms are on the reactants and products side?

Reactants: 8 atoms; Products: 8 atoms

Reactants: 4 atoms; Products: 2 atoms

Reactants: 2 atoms; Products: 1 atoms

Reactants: 3 atoms; Products: 2 atoms

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Balance the 'Separate Water' reaction. How many total molecules and how many total atoms are on each side of the balanced equation?

2 molecule
3 molecules
6 molecules
1 atom
2 atoms
3 atoms
6 atoms
9 atoms

Reactant side
Product side

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Balance the 'Combustion of Methane' reaction. How many total molecules and how many total atoms are on each side of the balanced equation?

1 molecule
2 molecules
3 molecules
1 atom
2 atoms
4 atoms
6 atoms

Reactant side
Product side

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Which of the following statements about balanced chemical equations is correct?

Neither the number of atoms or the number of molecules needs to be equal between reactants and products.

The number of molecules on the reactant side is always equal to the number of molecules on the products side.

The number of atoms on the reactant side is always equal to the number of atoms on the products side.

The number of molecules and atoms are always equal to each other on both sides of the chemical equation.

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Play Level 1 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
Write down two strategies that you used to balance chemical equations.

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Play Level 2 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
What do you find most difficult about balancing chemical equations so far?

For questions 13-20, state how many of each atome there is. See the example below:

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Answer: 4, 2

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Consider the equation from the 'Making Ammonia' example:
What are the numbers in green and blue called, and what do they represent?

Subscripts
Coefficients
The number of a specific type of atom
The number of molecules

Green numbers
Blue numbers

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The equation from the previous question can also be written as follows:
How is this equation different from the one in the previous question?

There is no number in place of the '1'

Each coefficient is different

Each subscript is different

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Which of the following coefficients could you use in a balanced chemical equation?

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If you were balancing an equation containing the O₂ molecule, which of the following would be correct representations of O₂ and its coefficient?

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Examine equation a and equation b below. Both are balanced, but equation b is the correct way to write a balanced equation:
Answer the following questions:
What is the relationship between the coefficients in equations a and b?
How can you check if an equation is written in the correct way after you've balanced it?

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Play Level 3 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
Are there any other strategies you found for balancing?

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Following along with your teacher, click on the 'show your work' box below and balance the equation.
Enter the coefficients in the following format:
a, b, c, d
where a is the first coefficient, b is the second, c is the third, and d is the fourth.

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Following along with your teacher, click on the 'show your work' box below and balance the equation.
Enter the coefficients in the following format:
a, b, c, d
where a is the first coefficient, b is the second, c is the third, and d is the fourth.

Now that you've been introduced to balancing equations, it's time to do some practice. The key thing to remember about balancing chemical equations is that it is a trial and error process. Don't be afraid to try something, erase it, try something else, erase that, try another thing - you get the picture.

A few reminders and hints as you work through these...

You may only change the coefficients - never change the subscripts!
If polyatomic ions are on both sides of the equation, treat them as a unit and balance them first.
Balance the metals, then the nonmetals.
If the equation has O₂ or H₂, balance those last.
For combustion reactions, balance carbon first, hydrogen second, and oxygen last (C-H-O)
Make sure that the coefficients are in the most reduced ratio.

Answer at least four questions between 29-35.

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Answer at least six questions between 36-43. You may use the 'show your work' box if you like.

Type the coefficients in order with commas and spaces between, like this:

a, b, c, d

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Answer at least six questions between 44-51. You may use the 'show your work' box if you like.

Type the coefficients in order with commas and spaces between, like this:

a, b, c, d

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02.08.21 - Balancing Chemical Equations

Balancing Chemical Equations

Part 1: PhET Simulation

02.08.21 - Balancing Chemical Equations

Balancing Chemical Equations

How are you doing today?

What was the highlight of your weekend?

Examine the following reaction, then identify the reactants and products:H2O2 --> H2O + O2

Compare and contrast reactants and products in a chemical reaction.

Part 1: PhET Simulation

What does the smiley face in the simulation indicate?

Balance the 'Make Ammonia' reaction. How many total molecules are on the reactants and products side?

Balance the 'Make Ammonia' reaction. How many total atoms are on the reactants and products side?

Balance the 'Separate Water' reaction. How many total molecules and how many total atoms are on each side of the balanced equation?

Balance the 'Combustion of Methane' reaction. How many total molecules and how many total atoms are on each side of the balanced equation?

Which of the following statements about balanced chemical equations is correct?

Play Level 1 of the Balancing Equation game. Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)Write down two strategies that you used to balance chemical equations.

Play Level 2 of the Balancing Equation game. Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)What do you find most difficult about balancing chemical equations so far?

Consider the equation from the 'Making Ammonia' example:What are the numbers in green and blue called, and what do they represent?

The equation from the previous question can also be written as follows:How is this equation different from the one in the previous question?

Which of the following coefficients could you use in a balanced chemical equation?

If you were balancing an equation containing the O2 molecule, which of the following would be correct representations of O2 and its coefficient?

Play Level 3 of the Balancing Equation game. Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)Are there any other strategies you found for balancing?

Following along with your teacher, click on the 'show your work' box below and balance the equation.Enter the coefficients in the following format: a, b, c, d where a is the first coefficient, b is the second, c is the third, and d is the fourth.

Following along with your teacher, click on the 'show your work' box below and balance the equation.Enter the coefficients in the following format: a, b, c, d where a is the first coefficient, b is the second, c is the third, and d is the fourth.

How are you doing today?

What was the highlight of your weekend?

Examine the following reaction, then identify the reactants and products:H2O2 --> H2O + O2

Compare and contrast reactants and products in a chemical reaction.

What does the smiley face in the simulation indicate?

Balance the 'Make Ammonia' reaction. How many total molecules are on the reactants and products side?

Balance the 'Make Ammonia' reaction. How many total atoms are on the reactants and products side?

Balance the 'Separate Water' reaction. How many total molecules and how many total atoms are on each side of the balanced equation?

Balance the 'Combustion of Methane' reaction. How many total molecules and how many total atoms are on each side of the balanced equation?

Which of the following statements about balanced chemical equations is correct?

Play Level 1 of the Balancing Equation game. Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)Write down two strategies that you used to balance chemical equations.

Play Level 2 of the Balancing Equation game. Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)What do you find most difficult about balancing chemical equations so far?

Na:___ O:___ H:___

H:___ S:____

Zn:___ Cl:___

Al:___ S:___

C:___ H:___ O:___

Ba:___ C:___ H:___ O:___

Sn:___ Cr:___ O:___

N:___ O:___ H:___

Consider the equation from the 'Making Ammonia' example:What are the numbers in green and blue called, and what do they represent?

The equation from the previous question can also be written as follows:How is this equation different from the one in the previous question?

Which of the following coefficients could you use in a balanced chemical equation?

If you were balancing an equation containing the O2 molecule, which of the following would be correct representations of O2 and its coefficient?

Play Level 3 of the Balancing Equation game. Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)Are there any other strategies you found for balancing?

Following along with your teacher, click on the 'show your work' box below and balance the equation.Enter the coefficients in the following format: a, b, c, d where a is the first coefficient, b is the second, c is the third, and d is the fourth.

Following along with your teacher, click on the 'show your work' box below and balance the equation.Enter the coefficients in the following format: a, b, c, d where a is the first coefficient, b is the second, c is the third, and d is the fourth.

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

What are the coefficients?

Na:___ O:___ H:___

H:___ S:____

Zn:___ Cl:___

Al:___ S:___

C:___ H:___ O:___

Examine the following reaction, then identify the reactants and products:
H₂O₂ --> H₂O + O₂

Play Level 1 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
Write down two strategies that you used to balance chemical equations.

Play Level 2 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
What do you find most difficult about balancing chemical equations so far?

Consider the equation from the 'Making Ammonia' example:
What are the numbers in green and blue called, and what do they represent?

The equation from the previous question can also be written as follows:
How is this equation different from the one in the previous question?

If you were balancing an equation containing the O₂ molecule, which of the following would be correct representations of O₂ and its coefficient?

Play Level 3 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
Are there any other strategies you found for balancing?

Following along with your teacher, click on the 'show your work' box below and balance the equation.
Enter the coefficients in the following format:
a, b, c, d
where a is the first coefficient, b is the second, c is the third, and d is the fourth.

Following along with your teacher, click on the 'show your work' box below and balance the equation.
Enter the coefficients in the following format:
a, b, c, d
where a is the first coefficient, b is the second, c is the third, and d is the fourth.

Examine the following reaction, then identify the reactants and products:
H₂O₂ --> H₂O + O₂

Play Level 1 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
Write down two strategies that you used to balance chemical equations.

Play Level 2 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
What do you find most difficult about balancing chemical equations so far?

Na:_ O:_ H:___

H:_ S:__

Zn:_ Cl:_

Al:_ S:_

C:_ H:_ O:___

Ba:_ C:_ H:_ O:_

Sn:_ Cr:_ O:___

N:_ O:_ H:___

Consider the equation from the 'Making Ammonia' example:
What are the numbers in green and blue called, and what do they represent?

The equation from the previous question can also be written as follows:
How is this equation different from the one in the previous question?

If you were balancing an equation containing the O₂ molecule, which of the following would be correct representations of O₂ and its coefficient?

Play Level 3 of the Balancing Equation game.
Take a screenshot of your score and put it in the 'Show Your Work' box below. (Don't know how to take a screenshot? Click here to find out how!)
Are there any other strategies you found for balancing?

Following along with your teacher, click on the 'show your work' box below and balance the equation.
Enter the coefficients in the following format:
a, b, c, d
where a is the first coefficient, b is the second, c is the third, and d is the fourth.

Following along with your teacher, click on the 'show your work' box below and balance the equation.
Enter the coefficients in the following format:
a, b, c, d
where a is the first coefficient, b is the second, c is the third, and d is the fourth.

Na:_ O:_ H:___

H:_ S:__

Zn:_ Cl:_

Al:_ S:_

C:_ H:_ O:___

Ba:_ C:_ H:_ O:_

Sn:_ Cr:_ O:___

N:_ O:_ H:___