Chemical Reactions and Matter

Chemical Reactions Make Up Day

KCP Chemistry

​Instructions...

​Completion of this lesson will serve as a make up grade for selected practice grades. The ENTIRE lesson must completed and the score recieved will go in the gradebook as the replacement score.

​Be sure to submit selected replacement assignments

Multiple Choice

The Law of Conservation of Mass states

• that matter exists in all states and reacts the same
• that matter can only be changed into new substances by introducing a catalyst
• that matter exists in the same state throughout any chemical change
• that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants

Multiple Choice

What is the BEST definition of a chemical reaction?

• A change in matter that produces one or more NEW substances

• When two things combine and EXPLODE.

Multiple Choice

What is the term for the → sign in a reaction?

• makes
• produces
• yields
• all are correct

Multiple Choice

If an element is diatomic it should have a subscript of___

• 1, always

• 2, only when it is an element

• it shouldn't have a subscript, it should have a coefficent

• 2, when bonded in a compound

Multiple Choice

What are the reactants in the chemical equation pictured?

• CH₄ and CO₂
• CH₄ and O₂
• CO₂ and H₂O
• O₂ and H₂O

Multiple Choice

___________________ are the elements/compounds formed in a chemical reaction (on the right)

• Polymers
• Bonds
• Reactants
• Products

Definition of a Chemical Reaction

​The process of breaking chemical bonds in one or more substances to reform bonds and create new substances

Multiple Choice

Which one shows that a chemical reaction has occurred?

• dissolving

• melting

• formation of a gas

• bending

Multiple Select

Which of the following are evidence of a chemical reaction?

• Formation of a solid

• Color Change

• Formation of a gas

• Release of Energy/Heat

​Steps to Balancing an Equation

​1. Determine the number of atoms for each element.

2. Pick an element that is not equal on both sides of the equation.

3. Add a coefficient in front of the formula with that element and adjust your counts.

4. Continue adding coefficients to get the same number of atoms of each element on both sides

Multiple Choice

Is this balanced?...
Al + O₂ --> 2Al₂O₃

• Yes!
• NO!

Multiple Choice

Is this balanced?...
Fe + S --> FeS

• YES!
• NO!

Multiple Choice

The red numbers in the image below represent ________

• subscripts
• coefficients
• I don't know, and don't want to try
• None of the answers are correct

Multiple Choice

The number of atoms you begin with in a chemical reaction ...

• must be the same as the number of  atoms you end with
• must be an even number
• can be different to the number you finish with
• changes depending on how much energy is formed

Multiple Choice

Choose the balanced chemical equation for the formation of iron oxide.

• 2Fe + O₂ → 2FeO₂
• Fe + O₂ → FeO₂
• 4Fe + 3O₂ → 2Fe₂O₃
• 4Fe + O₂ → 2FeO₂

Multiple Choice

Balancing the following:

____ Al + ____ HCl → ____ AlCl₃ + ____ H₂

• 1,3,1,2
• 2,3,2,3
• 2,6,2,3
• 3,2,6,2

Multiple Choice

Balance this reaction:

____ Na₃PO₄ + ____ KOH ---> ____ NaOH + ____ K₃PO₄

• 1,3,3,1

• 1,3,2,1

• 2,3,3,1

• 1,1,3,1

​Synthesis Reactions

​Also known as “combination” reactions

Definition: Two or more elements combine to make a new compound.

Multiple Choice

Without balancing the final equation, predict the products for the synthesis reaction:  $$Li\ +\ Cl_2\ \rightarrow$$  ?

• $$LiCl_2$$  

• $$LiCl_{ }$$  

• $$Li_2Cl_2$$  

• $$Li_2Cl_{ }$$  

Multiple Choice

Without balancing the final equation, predict the products for $$Al\ +\ Cl_{2\ }\rightarrow\ ?$$  

• $$Al_3Cl$$  

• $$AlCl$$  

• $$AlCl_3$$  

• $$Al_3Cl_2$$  

Multiple Choice

A synthesis reaction can be represented as ________________________.

• AB + CD → AC + BD
• AB → A + B
• A + B → AB
• A + BC → B + AC

Multiple Choice

This chemical equation for magnesium oxide is an example of what type of reaction?
2Mg + O₂  → 2MgO

• decomposition reaction
• synthesis reaction
• single displacement reaction
• combustion reaction

Multiple Choice

Which of the following is an example of synthesis?

• Na + Br₂ --> NaBr
• KClO₃ --> KCl + O₂
• HgO + Cl₂-->HgCl + O₂
• Cl₂ + NaBr --> NaCl + Br₂