Chemical Reactions Lesson

Chemical
Reactions

A chemical reaction is a process in which one set of chemical substances is transformed into another. During this process, atoms are rearranged, and energy is released or absorbed as new products are formed.

The law of conservation of mass states that in a closed system, the total mass remains constant during a chemical reaction. This happens because atoms, which are the building blocks of matter, are neither created nor destroyed during the reaction. Instead, they are rearranged to form new substances.

​Law of Conservation of Mass

​This is why we balance equations!

​A balanced equation has the same number of each atom on each side of the equation.

​Reactants - what you start with

Products - what you end up creating

Dropdown

Ba₃N₂ + ​

Select answer

​ Fe₂O₃ ==> ​

Select answer

BaO + 2 FeN

Multiple Choice

What are the coefficient used to balance the equation below?
__Ag₂O →__ Ag +___O₂

• 2,4,1
• 1,1,1
• 2,1,2
• 2,2,2

Drag and Drop

​ MgF₂ + ​ Li₂CO₃ → ​ MgCO₃ + ​

Placeholder

LiF

Drag these tiles and drop them in the correct blank above

2

1

3

Signs that a Chemical Reaction Happened

• An unexpected color change

• Gas is formed (bubbles!)

• Change in temperature

  • exothermic - released heat

  • endothermic - absorbed heat

• New smell

• Sound or light is produced

• A precipitate is formed →

​There are five main types of chemical reactions.

Drag and Drop

Na₂O + H₂ → H₂O + ​

Placeholder

Drag these tiles and drop them in the correct blank above

H2

NaO

NaH

O2

Na

NaOH

Multiple Choice

Identify the following chemical reaction.

2 NaBr + 1 Ca(OH)₂ ----> 1 CaBr₂ + 2 NaOH

• Synthesis (or combination)

• Decomposition

• Single displacement

• Double displacement

Multiple Choice

Identify the following chemical reaction.

Pb + FeSO₄ ----> PbSO₄ + Fe

• Synthesis (or combination)

• Decomposition

• Single displacement

• Double displacement

Multiple Choice

In a chemical reaction, elements and/or compounds to the right of the arrow are called ______________.

example: H₂ + O₂ → H₂O

• Products
• Yields
• Molecules
• Reactants

Multiple Choice

What type of reaction is the equation 2NaCl →2Na +Cl₂?

• Synthesis Reaction
• Decomposition Reaction
• Single Displacement Reaction
• Double Displacement Reaction

When you predict a product, it is important to know how to write a formula

​You have rules and flowcharts to help you write the names and formulas for both ionic and covalent compounds. Here are a few things to remember:

1. Is the first element a metal? If it is, then you have to look at the charges on the ions. If it is not, then you will use the prefixes.

2. If the first element is a metal, is it a transition metal, or a metal like Pb or Sn? If so, you will need to remember in the name the charge is a Roman numeral in ( ).

3. No matter what type of compound it is, change the ending of the second element to IDE, unless the second part is a polyatomic ion.

4. Use your polyatomic ion charts to find the name, formula and charge on polyatomic ions. Do not change the name or formula of a polyatomic ion.

Multiple Choice

What is the formula for nitrogen dioxide

• NO(g)

• N₂O₂(g)

• NO₂(g)

• Na₃N(s)

• Na₂O(s)

Multiple Choice

What is the correct formula for sodium oxide?

• NaO(s)

• NaN(s)

• NO(g)

• Na₂O(s)

• N₂O₂(g)

Multiple Choice

Name for Hg₂S

• mercury (IV) sulfide

• mercury (III) sulfide

• mercury (II) sulfide

• mercury (I) sulfide

Multiple Choice

Name for LiOH

• lithium hydrogen oxide

• lithium hydroxide

• lithium (II) hydroxide

• lithium (I) hydroxide

Multiple Choice

Formula for iron (II) carbonate

• FeCO₃

• Fe₂CO₃

• FeCO₂

• Fe₂CO₂