Balancing Chemical Equations

Chemical Reactions

Vocabulary

How to Balance Equations

Counting Atoms

100

What is the Reactant of the chemical equation and where is it located?

The reactant is the original equation and it is always located on the left side of the equation.

100

By definition, the Law of Conservation of Mass states that matter (mass) may not be __________ nor _________ .

created / destroyed.

100

Balance the following equation: _____H₂ + ____O₂ ---> ____H₂O

2 H2 + O₂ ---> 2H₂O

100

What is the FIRST step to balancing chemical equations?

Count the atoms on both sides

100

How many atoms total?

H₂CO₃

200

What is the Product of a chemical equation and where is it located?

The product is the chemical change or new substance. It is always located on the right side of the equation.

200

This is the force that holds atoms in a compound together.

CHEMICAL BOND

200

Balance the following Equation: _____KClO₃ ---> KCl + ______O₂

2KClO₃ ---> 2KCl + 3O₂

200

Which part of the chemical equation are you to add or change.

The Coefficients

200

How many atoms total?

(NH₄)₂S

300

Identify the reactants and products in the following chemical equation: H₂ + NaCl ---> H₂Na + Cl + S

Reactants: H₂NaCl Products: H₂Na, Cl, S

300

12 grams of reactant X react with 15 grams of reactant Y. What is the total mass of the products?

27 grams

300

Balance the following equation: ____C₃H₈ + _____O₂ ---> ____CO₂+ ____H₂O

C₃H₈ + 5O₂ ---> 3CO₂ + 4H₂O

300

Within a chemical formula, if you don't see a subscript, you can conclude that there are how many atoms of that element within each molecule.

One

300

How many atoms total?

3Mg(OH)₂

400

What does the law of conservation of mass states?

What does it mean for chemical equations?

The law of conservation of mass states that matter can neither be created nor destroyed.

For balancing it means the number of atoms of each element must be equal before and after the reaction.

400

What are broken and formed in chemical reactions?

Chemical bonds

400

Balance the following equation: ____P + _____O₂ --->_____P₂O₅

4P + 5O₂ ---> 2P₂O₅

400

Which part of chemical equations can we NOT CHANGE?

The subscripts

400

How many atoms total?

2Sr(CH₃COO)₂

500

How many atoms does each element have in the following chemical equation WHEN IT IS BALANCED: NaOH + H₂CO₃ ---> Na₂CO₃ + H₂O

2Na, 5O, 4H, 1C

500

How could you speed up chemical reactions? (hint: think back to your inquiry lab in September)

Answers may vary, but could include: higher temperature, higher concentration of reactants, or increased surface area.

500

Balance the following equation: ___NaBr + ____CaF₂ ---> ____NaF + ____CaBr₂

2NaBr + CaF₂ ---> 2NaF + CaBr₂

500

Why do we need to balance chemical equations?

To ensure the Law of Conservation of Mass is followed.

500

How many HYDROGEN atoms total?

6C₂H₅(OH)₃