2/6/12 States Of Matter-Lab Reflection

LAB 1-Chemical Changes and Reactions (Candles and Carbon Dioxide)

CANDLES

Procedure and Observations:

1. Observe the green candle

Physical Description: Green, Smooth, Hard, Solid.

2. Light the green candle

-Change: Chemical

-Chemical Description: Combustible

3. Blow out the green candle

4. Light the white candle

-Change: Chemical

5. Mix some vinegar and baking soda in the beaker

-Result: Chemical Reaction-Carbon Dioxide is formed

6. Carefully "pour" the carbon dioxide (not the liquid) onto the candle

-Candle goes out

Conclusion:

When the carbon dioxide surrounded the candle, the flame did not have enough oxygen to burn. This means that some chemical changes require another element, in this case oxygen, to work. The carbon dioxide suffocated the flame by taking away the element it needed to burn. When you cover a candle to put out the flame, you are actually forcing it to burn off the remaining oxygen inside the sealed area, causing it to suffocate itself.

LAB 2- Burning Sugar (Marshmallows and Sugar Cubes Combined)

MARSHMALLOWS

Procedure and Observations: 

1. Tear the small marshmallow

--Inside: Soft, stick. Solid.

--Outside: Soft, Rough, Not Sticky. Solid.

2. Taste the marshmallow

--Taste: Sweet

--Texture: Soft

3. Take a large marshmallow and put it at the end of the stick

4. Burn the Marshmallow until it has completely become a dark brown color.

--Outside: 

-Texture: Crispy brown shell

-Change: Chemical

5. Taste the burnt marshmallow

--Inside:

-Texture: Gooey liquid-like substance

-Change: Physical

-Taste: Bitter

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SUGAR CUBES

Procedure and Observations:

--Sugar cube:

Hard, Rough. Solid.

1. Crush two sugar cubes and mix them in a cup of water

-Change: Physical (still sugar)

2. Crush another sugar cube and place it in a test tube

-Change: Physical (crushing)

3. Heat the test tube until sugar melts and turns brown

-Change: Chemical (forming new substance

4.Break open test tube and examine burnt sugar

{Observations for burnt sugar above in "MARSHMALLOWS"}

Conclusion:

When a physical change takes place, the substance does not change at a molecular level. For example when the sugar was diluted in the water, this was a physical change. The substance remained sugar, just in a less pure state. When a Chemical change takes place, the substance changes at the molecular level, and forms a new substance. For example when you burn wood to create a fire, creating ashes. Or, in this case burning sugar, which creates a bitter brown substance that resembles ash.

CHEMICAL CHANGE:

PHYSICAL CHANGE: