Chemical Reactions (Samin Davari)
Title: Chemical Reactions
Principle(s) Investigated: Identification of a chemical reaction, chemical change vs. physical change
Standards : MS-PS1-2. Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
Materials: Beakers, sugar, Concentrated sulfuric acid, glass stirring rod, googles, gloves
Procedure:
1) How do we know a chemical reaction has occurred? What are some changes you may see?
2) Describe the reactants we are starting with.
**Show Demonstration**
3) Identify a change you witnessed that indicates a chemical reaction has occurred.
**Re-watch recorded demonstration if needed**
4) What may be some reasons we need to conduct this in a fume hood?
Student prior knowledge: The difference between chemical and physical changes.
Explanation:
First, ask student to respond to the following questions in the Quickwrite:
1) How do we know a chemical reaction has occurred? What are some changes you may see?
2) Describe the reactants we are starting with.
*Discuss responses*
Safety: Wear proper protective equipment including gloves and safety glasses when preparing and performing this demonstration. Sulfuric acid is a very strong acid and is extremely corrosive to skin. Stand clear of the beaker as steam is generated during this reaction and contact with these vapors can cause burns.
Disposal: Residue should be rinsed thoroughly with water and discarded in a solid waste container.
Second, conduct the demonstration in fume hood:
- Put sugar in glass beaker, fill about 1/3 of the way
- Add sulfuric acid until sugar is saturated (you may have to stir slightly with glass rod)
- Watch the reaction and have students note any observations
Third, have student respond to the following questions in the Quickwrite:
3) Identify a change you witnessed that indicates a chemical reaction has occurred.
4) What may be some reasons we need to conduct this in a fume hood?
*Discuss responses*
Finally, show the following video: Thirst For Science
C12H22O11 + H2SO4 → C + H2O + water/acid mixture
Sulfuric acid is used as a dehydrating agent*
Questions & Answers:
1) How do we know a chemical reaction has occurred? What are some changes you may see?
2) Describe the reactants we are starting with.
3) Identify a change you witnessed that indicates a chemical reaction has occurred.
4) What may be some reasons we need to conduct this in a fume hood?
Applications to Everyday Life:
Can you think of chemical reactions we experience or see in our everyday lives? Chemical reactions are all around us, it is important for us to be able to identify them. Chemical reactions play a vital role in health, pharmaceuticals, engineering, climate control, carbon emissions, and so much more. We can use chemical reactions to make every day life better.
Every time we cook or clean, a chemical reaction is occurring!
Photographs:
Videos: Thirst For Science