Balancing, Conservation and Reaction Types Review

Chemistry Review 1

Definition:

A chemical reaction is when a reactant changes into a product.​

Some text here about the topic of discussion

​Parts of a Chemical Equation

In the Equation, H₂ + O₂ -> H₂O...

• H₂ and O₂ are reactants

• H₂O is the product

​The chemical symbols show us the composition of a molecule.

The subscripts tell us the number of atoms in each molecule.​

Coefficients tell us the number of molecules present.

Subject | Subject

Some text here about the topic of discussion

Balancing Chemical Equations

When you balance chemical equations, you add to the coefficient to balance the number of atoms on each side of the chemical equation.

​ In 2H₂ + O₂ -> 2H₂O

• 2 is the coefficient for H₂O

  • ​this means that we have two molecules of H₂O instead of one molecule.

​

Fill in the Blank

Balance the following equation:

NaCl > Na + Cl₂

Fill in the Blank

Balance this equation:

C₂H₆ + O₂ > CO₂ + H₂O

Fill in the Blank

Balance the following equation:

(NH₄)₃PO₄ + KOH > K₃PO₄ + NH₄OH

Why do we balance?

Law of Conservation of Mass

This law states that atoms are never created nor destroyed in a chemical reaction. They are only rearranged.

Some text here about the topic of discussion

Multiple Choice

Based on the law of conservation of mass, balancing chemical reactions helps show how matter is _______ during a chemical reaction.

• created or destroyed

• rearranged

• changed at the atomic level

• neither created nor destroyed

Reaction Types

There are 5 different types of reactions:

• Synthesis: two or more reactants combine to form a larger molecule.

• Decomposition: a larger molecule breaks up into smaller molecules.

• Single Replacement: when one atom replaces another atom.

• Double Replacement: when two atoms in different molecules are replaced.

• Combustion​: reactants are C_xH_y and O₂ hydrocarbons. Products are CO₂ and H₂O.

Fill in the Blank

Identify the following chemical reactions:

H₂O + C --> H₂ + CO₂

Ca(OH)₂ -->  CaO + H₂O

SO₂  +  O₂ ->  SO₃

NaCl  +  AgNO₃   -> AgCl  +  NaNO₃