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TAKS Objective 3 Substances have chemical and physical properties.

TEKS Science Concepts 8.9 The student knows that substances have chemical and physical properties. The student is expected to: (A) demonstrate that substances may react chemically to form new substances; (C) recognize the importance of formulas and equations to express what happens in a chemical reaction; and (D) identify that physical and chemical properties influence the development and application of everyday materials such as cooking surfaces, insulation, adhesive, and plastics.

Learning Objectives 1.  The student will demonstrate chemical change as evidenced by a change in color. 2.  The student will measure temperature change as the result of a chemical reaction. 3.  The student will demonstrate a chemical reaction that produces gases. 4. The student will demonstrate a chemical change that results in the formation of a precipitant. 5. The student will use models to explain chemical formulas.

Chemicals are only found in chem labs MISCONCEPTIONS True or False Chemicals are only found in chem labs

Chemistry runs everyone and everything!

Physical and chemical changes never happen at the same True or False Physical and chemical changes never happen at the same

Energy changes during a chemical reaction True or False Energy changes during a chemical reaction always give off heat

Energy changes during chemical reactions can give off heat and get hotter, absorb heat and get colder, give off light, sound, and electricity, etc.

Background

Physical vs Chemical Change

Alter the size &/or shape Physical Changes Alter the size &/or shape Cut, grind, dissolve

Physical Changes Phase Changes

Easily changed back to original form Physical Changes Easily changed back to original form

Chemical Changes New stuff is made Cannot change new stuff back into original form easily Chemical composition of new substance is different from original

Hint- Can you turn cooked chicken back into raw chicken? Physical or Chemical? Hint- Can you turn cooked chicken back into raw chicken?

5 Evidences of Chemical Change Smell Change Color Change Energy change (hot, cold, light, sound, electricity, etc.) Bubbles, fizzing, gas produced Precipitate (2 clears make a cloudy)

Baked cupcakes smell differently than batter #1 Smell Change Baked cupcakes smell differently than batter

#2 Unexpected Color Change Colorless methane burns blue

As candle was burns, it gives off heat and light #3 Energy Change As candle was burns, it gives off heat and light

Alka Seltzer in water makes carbon dioxide gas #4 Bubbles or Fizzing Alka Seltzer in water makes carbon dioxide gas

Two clear solutions make a cloudy solution #5 Precipitate Two clear solutions make a cloudy solution

Physical or Chemical? You decide. . . How do you know?

Physical or Chemical? You decide. . . How do you know?

Physical or Chemical? You decide. . . How do you know?

ENGAGE Balloon Gas What happened?

EXPLORE Red Light – Green Light For the Rust of My Life Take a Powder Clabbered Clumps Witches Brew Bubble Bubble Toil & Trouble Fireworks (do as demo) Milk of Magnesia

EXPLAIN Every reaction we did shows evidence of chemical change- what are 5? Please- Precipitate (2 clears make cloudy) Excuse- Energy change (heat, light, sound, electricity) Coughs- Color change (unexpected) Sneezes- Smell Change Burps- Bubbles or fizzing (gas produced)

ELABORATE Abracadabra Sweet Models Irreversible Consequences Chemistry at Home List or digital/ paper photos in PPT or poster

EVALUATE How many atoms of copper in 2 molecules Cu2O? What happens to atoms in chemical reactions? What physical properties can change in a chemical reaction?