Balancing Reactions

What is the little number after an element in a chemical equation called.
Example: H₂

• Coefficient 
• Subscript
• Atom
• Equation

What does the Law of Conservation of Mass state?

• Matter cannot be gained or lost in a chemical reaction.
• Matter can only be lost in a chemical reaction.
• Matter can only be gained in a chemical reaction.
• Matter can be gained and lost in a chemical reaction. 

What is the left part of a chemical equation called?
2H_{2 +} O₂ --> 2H₂O

• Reactants
• Products 
• Yields 
• Chemical Equation 

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

Which of the following equations are correctly balanced?

• 12CO₂ +H₂O --> C₆H₁₂O₆ + O₂
• CO₂ + 9H₂O --> C₆H₁₂O₆ + O₂
• CO₂ + H₂O --> 3C₆H₁₂O₆ + O₂
• 6CO₂ + 6H₂O --> C₆H₁₂O₆ + 6O₂

What coefficient should be used to make the following equation balanced?
N₂+O₂--> _NO 

• 1
• 2
• 3
• 4

Which problem is balanced?
(Check ALL answers)

• PbO₂ + 2H₂
• SO₂ + H₂0 --> H₂SO₄
• 2Na + 2H₂O --> 2NaOH + H₂

Balance this equation

_Al +_HCl --> _H₂ +_AlCl₃

• 2,6,3,2

• it's already balanced

• 4,12,3,4

• 2,1,4,5

Balance the following equation:

___ Mg+ ___ O₂→___ MgO

• 1, 1, 3

• 2, 1, 2

• 1, 2, 1

• 2, 2, 2