Balancing Chemical Equations

What does the Law of Conservation of Mass state?

• Matter cannot be created or destroyed in a chemical reaction.

• Matter can only be destroyed in a chemical reaction.

• Matter can only be created in a chemical reaction.

• Matter can be created and destroyed in a chemical reaction.

Is the following equation balanced?...
Al + O₂ --> 2Al₂O₃

• Yes!
• No!

What is the number before a chemical formula called?
Ex: 2H₂ + O₂ --> 2H₂O

• Coefficient
• Subscript
• Atom
• Equation

Is the following equation balanced?
2C₂H₂ + 5O₂ --> 4CO₂ + 2H₂O

• yes
• no

The coefficient in 3H₂O is

• 6

• 5

• 2

• 3

Which of the following models best demonstrates a balanced chemical equation?

• F

• G

• H

• J

What coefficient should be used to make the following equation balanced?

N₂+O₂--> __?__NO

• 1

• 2

• 3

• 4

• H₂ + O

• reactant(s)

• →

• reaction 

  (into)

• H₂O

• product(s)

How many HCl molecules do you need to balance this equation?

2Mg + ​ (a)   HCl ---> 2MgCl₂ + 2H₂

• 4
• 1
• 2
• 3

What coefficient should be used to make the following equation balanced?

N₂+O₂--> __?__NO

• 1

• 2

• 3

• 4