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.

Chemical Equation

• A representation of a chemical reaction

• the starting materials in a chemical reaction

• the new substances that are formed in a chemical reaction

• tells how many atoms, molecules, or formula units take part in a reaction

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

• yes

• no

Balance this equation

_Al +_HCl --> _H₂ +_AlCl₃

• 2,6,3,2

• it's already balanced

• 4,12,3,4

• 2,1,4,5

The coefficient in 3H₂O is

• 6

• 5

• 2

• 3

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

• 3
• 6
• 12
• 24

How many Hydrogen are in 4H₂O?

• 6
• 8
• 2
• 4

How many Sodium (Na) are in 6NaCl?

• 1
• 12
• 6

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

• yes

• no

Balance this equation

_Al +_HCl --> _H₂ +_AlCl₃

• 2,6,3,2

• it's already balanced

• 4,12,3,4

• 2,1,4,5