Balancing Chemical Equations

Balancing Chemical Equations

Fall 2020

Fill in the Blank

The law of ______________ of mass says that matter cannot be created nor destroyed.

REMEMBER

# of each element in reactants

MUST EQUAL

# of each element in products

2Al₂(CO₃)₃

• Al: 4 because 2 x 2 = 4

• C: 6 because 2 x 3 = 6

• O: 18 because 3 x 3 x 2 = 18

A few hints:

• Water can often be split into H + OH, but not always

• Save O for last in a reaction that produces CO2 + H₂O

• Polyatomics can be left as one thing if it appears on both sides of the yield

• Balance everything other than O and H first

• Try to get rid of odd numbers first

Practice Problems

Number your paper 1 - 7

___ H₂ + ___ O₂ → ___H₂O

Balance this equation.

___SiO₂ + ___C → ___Si + ___CO

Balance this equation.

__AgNO₃ + __MgCl₂

→

__AgCl + __Mg(NO₃)₂

Balance this equation.

___H₂SO₄ + ___NaOH

→

___Na₂SO₄ + ___H₂O

Balance this equation.

__C₃H₈ + __O₂ → __CO₂ + __H₂O

Balance this equation.

__C₈H₁₈ + __O₂ → __CO₂ + __H₂O

Balance this equation.

Multiple Choice

Which of the pictures below shows a balanced representation of

H₂ + O₂ → H₂O?