Intro to Balancing

The Law of Conservation of Mass says that mass of all substances present before a chemical change is the same as that at the end of the reaction.

• True

• False

What is the left part of a chemical equation called?

2H₂ + O₂ ---> 2H₂O

• Reactants

• Yields

• Products

• Chemical equation

What is the right part of a chemical equation called?

2H₂ + O₂ ---> 2H₂O

• Reactants

• Yields

• Products

• Chemical Equation

What is the number before a chemical formula called?

Example: 2H₂ + O₂ ---> 2H₂O

• Coefficient

• Atom

• Subscript

• Equation

What is the little number after an element in a chemical equation called?

Example: H₂

• Coefficient

• Atom

• Subscript

• Equation

How many Oxygens are in this molecule? 
(OH)₂

• 4
• 1
• 2
• 3

What is the total number of atoms present in 5Na₃PO₄?

• 5

• 55

• 40

• 8

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

• 1
• 2
• 3
• 4

Is the following equation balanced?

Al + O₂ ---> 2Al₂O₃

• YES

• NO

What coefficients are needed to balance the equation?

___Al + ___ O₂ ---> 2Al₂O₃

• 3,2

• 3,4

• 4 , 3

• 4,2