OBJECTIVES

1
OBJECTIVES

• Observe an exothermic reaction.
• Differentiate between physical and chemical
  changes.

2
You will use the 0 C of the thermometer to take
the temperature readings.
3

• Place the thermometer in the jar and close the
  lid.

4

• Wait about 5 minutes for the thermometer to
  record the temperature.
• While you wait for thermometer to
  record the temperature, soak a piece of steel
  wool in vinegar for 1 minute.

5

• Squeeze the excess vinegar out of the steel wool.

• Wrap the steel wool around the end of thermometer
  and place them in the jar.

• Seal the jar.

6

• Wait 5 minutes, then read the
  temperature and compare it with the first
  reading.

7

• Did the temperature increase or decrease?
• What is the temperature difference?
• Did a chemical or physical change take place?

8
OBJECTIVES

• Observe an endothermic reaction.
• Distinguish between a chemical change
  and a physical change.

9

• Fill the jar with room temperature water.
• Put the thermometer in the jar.
• Wait 5 minutes then take the water temperature.

10

• While you wait to take the water temperature, put
  your hand on the outside of the jar and notice
  how cool or warm it is. RECORD YOUR OBSERVATION.

11

• Record the temperature of the water after 5
  minutes are up.
• Stir in the Epson salt.
• Fill the jar again. RECORD YOUR OBSERVATION.

12

• Wait 2 minutes and record the temperature of the
  Epsom solution.
• Record the temperature.

13

• Did the water temperature increase or decrease?
• What is the amount of temperature difference of
  the water before and after adding Epsom salt?

14

• Why did the temperature of the water change?
• Does mixing Epsom salt and water represent
  physical or chemical change or both?

15
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