Balancing Expressions and Equations

PCl₅ + ___ H₂O → ___ HCl + H₃PO₄

• 4, 5

• 1, 6

• 3, 8

• 2,2

__ Al + __ FeO → Al₂O₂ + __ Fe

• 1, 1, 2

• 2,1,2

• 2, 2, 2

• 2,4,2

 Mg  +  ___ HCl  →   MgCl₂  +   H₂

• 1
• 2
• 3
• 4

Which side of a chemical equation is the reactant side?

• Left (before the yields sign)
• Right (after the yields sign)

Which side of a chemical equation os the product side?

• Left (before the yields sign)
• Right (after the yields sign)

Which problem is balanced?

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

Balance this equation.
_SnO₂ +_H₂-->_Sn +_H₂O

• 1,1,2,1
• 1,2,1,1
• 1,2,1,2
• 1,2,2,1

Balance this equation.
_CF₄ + _Br₂ -- _CBr₄ + _F₂

• 2,1,2,1
• 1,2,2,1
• 1,2,1,2
• 2,2,2,2

What is the little number after an element in a chemical equation called.
Example: H₂

• Coefficient 
• Subscript
• Atom
• Equation

What does the Law of Conservation of Mass state?

• Matter cannot be gained or lost in a chemical reaction.
• Matter can only be lost in a chemical reaction.
• Matter can only be gained in a chemical reaction.
• Matter can be gained and lost in a chemical reaction.