Balancing Chemical Equations

Review Questions

Multiple Choice

Which is the correct chemical equation for the following: Solid Zn reacts with silver (I) chloride to produce Zinc (II) chloride and silver metal

• Zn + AgCl → ZnCl₂ + Ag

• ZnCl₂ + Ag → Zn + AgCl

• ZnCl2 + Ag₂ → Zn + AgCl

• Zn₂Cl + Ag → Zn + AgCl

Multiple Choice

Iron reacts with sulfur to produce iron(II) sulfide powder.

• 2Fe(s) + S(s) → Fe₂S(s)
• Fe(s) + S(s) → FeS(s)
• Fe(s) + S(g) → FeS(s)
• 4Fe(s) + S₂(g) → 2Fe₂S

Multiple Choice

Which of the following symbols is not a correct indication of the phase of a substance in a reaction? 

• (s)=solid
• (g)=grams
• (l)=liquid
• (aq)= aqueous

Multiple Choice

Which compounds are the PRODUCTS of this reaction?

• CO₂ + H₂O

• C₆H₁₂O₆ + O₂

• C₆H₁₂O₆ + CO₂

• H₂O + O₂

Balancing Chemical Equations


We will
1. Review the law of Conservation of Mass
2. The Rules of Balancing Chemical Equations

I will Practice and Apply what I have learned.

Law of Conservation of Mass

​According to the Law of Conservation of Mass, the mass of the reactants must equal the mass of the products.

Balancing Chemical Equations

As you can see, this equation needs to be balanced. There are not enough oxygen atoms on the product side.

Balancing Chemical Equations

Equations are balanced by inserting coefficients into the equation. Right now, the coefficients are 1 (Ones are not usually written)

​

​2

​2

Rules of Balancing Chemical Equations

1. Subscripts remain the same.

2. Coefficients have to be in front of the molecule.

Rules of Balancing Chemical Equations

A balanced equation is a ratio that must be expressed in straightforward whole numbers.

Let's Apply

​# atoms reactants	​# atoms products
​Fe	​Fe
​O	​O

Draw

Let me see you balance!

Multiple Choice

What coefficients are needed to balance the following chemical equation?

__Zn + __HCl → __ZnCl₂ + __H₂

• 1,1,1,1

• 1,2,1,1

• 2,1,2,2

• 2,1,2,1

Multiple Choice

What coefficients are needed to balance the following chemical equation?

__Fe + __ AgNO₃ → __ Ag + __ Fe(NO₃)₃

• 1,1,1,1

• 1,2,1,2

• 1,3,3,1

• 3,1,3,1