Chemical Reactions

Chemical Reactions

by Myranda Wilson

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​Learning Target:

• ​ I know

  • ​How to define chemical reactions

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​Success Criteria:

• ​ I can

  • ​write a chemical formula when given reactants and products

​Reaction...

​What does this word make you think of????

​What are everyday reactions

​English definition:

​- a response or change in a person as a result of a situation or stimulus

​

​Reactions include:

​1. emotional responses

​2. verbal responses

​3. behavioral responses

​

​Reactions are a change in our behavior based on the action of something else.

​Examples

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​How does this relate to physical science...

​A CHEMICAL reaction is a result or change in which one or more substances are converted into one or more different substances.

​- Chemical reactions take place all around us everyday

​Examples:

-​Baking a cake

- metals rusting

​-digesting food

​Parts of a chemical reaction

​A + B

​Reactants

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​

-​Reactants are starting material that will react

​- written on left side of the arrow

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​C + D

​Products

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​

​-Products are the new substances produced in the reaction.

​- Written on the right side of the arrow

Fill in the Blanks

What goes on the right side of the arrow?

Multiple Choice

Which of the following is one of the reactants from the following chemical equation?

CH₄ + O₂ ---> CO₂ + H₂O

• H₂O

• O₂

Multiple Choice

Which of the following is one of the products from the following chemical equation?

CH₄ + O₂ ---> CO₂ + H₂O

• H₂O

• O₂

​How do we know when a reaction has taken place?????

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​

​

​Any ideas??????

​We look for indicators (evidence of change)

​There are a few indicators of a chemical rxn:

​changes in ​color

• ​changes in temperature

  • gets hot or cold

• ​ production of gas

  • ​ex: bubbles

• ​formation of a precipitate

• ​production of light or sound

  • ​energy

​Production of Gas

​The formation of gas is a result of combining substances

• ​Examples:

  • ​bubbling

  • ​fizzing

  • ​foaming

​Formation of a precipitate

​Precipitates are solids that are produced as a result of a reaction in solution. It separates from the solution.

​Color Change

​Color change is an indication of substances that have been mixed and have produced a different color from the original substances.

​Change in temp.

​After the substances are mixed, the surrounding area becomes cooler or hotter than the original temperature.

​Production of light or sound

​This is when energy gets released by matter. You may see a flash of light or hear a sound such as a "pop" or "bark"

​Antoine Lavoisier

​French chemist who studied chemical rxns using scientific methods.

• ​Developed the law of conservation of mass

​Law of conservation of mass

​Law that states...

• ​In a chemical reaction (rxn), matter is not created nor destroyed, but is converted (transformed)

  • ​that the total mass of the products must always equal the total mass of the reactants

In other words....

​the amount you start with is the amount you end with

​What does this mean?

​Atoms cannot be created or destroyed in a reaction, they can only be rearranged

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This can be useful for determining the amount (mass) of a missing reactant or product​​

Multiple Choice

What does the law of conservation of mass mean?

• Matter can be created and destroyed

• Matter is neither created nor destroyed but is conserved

• Matter can't be created but can be destroyed 

Multiple Choice

The law of conservation states mass of the reactants is ____ the mass of the products

• Greater than

• less than

• equal to

Multiple Choice

If 14 grams of Aluminum (Al) and 23 grams of Oxygen (O) are mixed, what will be the total mass of the end product (Aluminum oxide)?

• 23 g

• 14g

• 40g

• 37g

Multiple Choice

25 grams of water can break down into 19 g of oxygen and _____ g of hydrogen 

• 6

• 24

• 19

• 25

Fill in the Blanks

grams of water break down into 82 g of oxygen and 21 g of hydrogen.