East High Chemistry Group

Name ______Period ______

Chapter 6 –Cool Chemistry Show

Activity 1 Outline: Chemical and Physical Changes (pg 433-440)

What do you see?

What do you think?

Investigate (pgs 433-435) Write your answers in the spaces provided.

1.  Your teacher will demonstrate several types of changes. For each one, record your observations, whether the change is chemical or physical and why you made that conclusion.

2.  Evidence you may look for includes color changes. formation of a precipitate (sometimes will turn a solution cloudy, formation of a gas (fizzing, bubbling).

3.  A physical changes involves changes in the sppearnace of the material but does not involve the creation of new substances. A chemical changes involves the creation of new substances.

Change / Observations / Chemical or Physical? / Evidence
Heating an ice cube.
Boiling a small amount of water
Melting wax
Breaking a wooden splint
Hold a wooden splint in a flame
Add a few drops of lemon juice to some milk.
Add some baking soda to vinegar
Add table salt to water.
Add iodine to starch

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Add some zinc to some hydrochloric acid.
Add phenolphthalein indicator to a sodium hydroxide solution
Add sodium carbonate to sodium hydrogen sulfate
Add a few drops of ammonia to a copper (ii) sulfate solution.
Add a few drops of vinegar to a small piece of chalk.
Sharpen a pencil and collect the shavings
Gently warm crystals of Iodine.
Tear a piece of paper
Bend a paper clip

Imagine a situation where 2 colorless substances are mixed together. There is no color change and no formation of a gas. However, the solution becomes warm as the 2 solutions are mixed. Even though dissolving is a physical process, it often results in a change in temperature, which can be either negative or positive depending on the solute and solvent. IS dissolving a chemical or physical change? Explain your choice.______

4.  Each group will be given some of the material found in disposable diapers.

a)  Predict how much water the diaper material will be able to hold ______

b)  How can you test this prediction? ______

c)  Perform your experiment. How much water did the material hold? ______

d)  Where you correct in your prediction? ______

e)  How does this compare to your results?______

f)  The diaper contains a material called sodium polyacrylate. When is absorbs water, is this a physical or chemical change? Explain your answer. ______

5.  Your teacher will show you a solution of sodium acetate in a 250ml flask. Observe the solution carefully.

a)  Record your observations ______

b)  Now Mrs Hanson will add 1 crystal of sodium acetate to the flask. Record your observations ______

c)  Was this a physical or chemical change? ______

6.  In a large jar, mix 150 ml of sodium silicate (sometimes called water-glass) and 400 ml of water. Carefully drop solid colored crystal compounds of nickel, iron, and/or manganese inside the jar

a)  Is there evidence of a change immediately? ______In several minutes? In several hours? In several days? ______Describe the results ______

b)  Is this a physical or chemical change? ______explain your answer. ______

Chem. Talk Notes pg. 436-437.


Checking Up pg. 437

1)Physical change ______

Example 1 ______Example 2 ______.

2)Solution______Solute______Solvent______.

3) Chemical change ______

Example 1 ______Example 2 ______.

4)______

5)______.

6) The difference between a saturated solution and a super saturated solution is ______

What do you think now?

Chem. To Go pg. 439

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1. Classify the following as physical or chemical changes and why.

a)  Toast turns black after being in the toaster too long. ______

b)  Water condenses on the outside of a glass of iced tea. ______

c)  Leaves turn orange, yellow and red in the fall. ______

d)  Green bananas turn yellow ______

e)  Milk becomes sour if left at room temperature ______

f)  Butter melts on hot days ______

4. Identify the physical and chemical properties of aluminum:

Physical:

Chemical:

7.  Explain if the decomposition of water is a physical or chemical process and why.

Reflection:

What did you learn from this activity?

How might you use this in your chapter challenge?

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