Balancing Chemical Equations

The Law of Conservation of Matter

• tells how many atoms of an element are contained in one molecule or formula unit.

• the starting materials in a chemical reaction

• the new substances that are formed in a chemical reaction

• A law stating that atoms are not created or destroyed during a chemical reaction.

Is the equation balanced?: 2H₂O + O₂ --> 4MgO + 3Fe

• yes

• no

How many atoms of carbon (C) are in C₆H₁₂O₆?

• 3
• 6
• 12
• 24

How many Hydrogen are in 4H₂O?

• 6
• 8
• 2
• 4

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

• Reactants
• Products 
• Yields 
• Chemical Equation 

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

• Reactants
• Products 
• Yields 
• Chemical Equation 

How many Mn atoms are found in the following compound?
3Cr(MnO₄)₆

• 3
• 4
• 6
• 18

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

• 1
• 2
• 3
• 4

Balance this equation:
 2Li + Cl₂ -> LiCl

• 2Li + Cl₂ -> 4LiCl2
• 2Li + Cl₂ -> LiCl₂
• 2Li + Cl₂ -> 2LiCl

Name the part in red:

H₂ + O₂ -> H₂O

• Coefficient
• Product
• Yield
• Subscript