Chemical Reactions Review

Balance this equation:
MgCl₂ --> Mg₄+ Cl₂

• It's already balanced.
• 4MgCl₂ --> Mg₄+ 4Cl₂
• 4MgCl₂ --> Mg₄+ 5Cl₂

Balance this equation:
 2Li + Cl₂ -> LiCl

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

In chemical reactions, what does the principle of conservation of mass mean?

• Matter is not created or destroyed.
• The total mass of the reactants is greater than the total mass of the products.
• The total mass of the reactants is less than the total mass of the products.
• Matter is not changed.
  

How many Hydrogen (H) atoms are in NH₃O5

• 3
• 4
• 5
• 1

Name the part in red:

H₂ + O₂ -> H₂O

• Coefficient
• Product
• Reactant
• Subscript

Is the following equation balanced or unbalanced ? 
Al + O₂ --> Al₂O₃

• Balanced
• Unbalanced

PCl₅ + ___ H₂O → ___ HCl + H₃PO₄

• 4, 5

• 1, 6

• 3, 8

• 2,2

 Mg  +  ___ HCl  →   MgCl₂  +   H₂

• 1
• 2
• 3
• 4

Which problem is balanced?

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

N₂ + H₂ = NH₄

• Balanced
• Unbalanced