Your Name: ___________________________________ Role:______________

Lab Partners: ________________Role:_____ ________________Role:_____

Problem: What is considered evidence for a chemical change?

Hypothesis: _______________________________________________________

_________________________________________________________________

_________________________________________________________________

Materials:                 balance                 Baking Soda
    100 mL beaker          hand lens               dropper
    3 M Hydrochloric Acid  watch glass             matches
    wood splint            hot plate               goggles

Caution:

Procedure:

1. Obtain goggles and wear them for the entire lab!
2. Place 0.5 g of Baking Soda into a 100 mL beaker. Look at the sample with a hand lens and record your observations.
3. Add one dropper full (about 1.0 mL) of the Hydrochloric Acid (HCl)
to the Baking Soda and immediately cover with a watch glass.
Observe the reaction and record your observations.
4. Repeat step 3, three more times, keeping the cover on the beaker.
5. Light a wood splint, remove the watch glass and place the lit wood splint in the beaker above the contents. Record your observations.
6. Place the beaker on a hot plate and heat until dry.
7. Let cool and observe the new substance with the hand lens. Record your observations.
8. Add one dropper full (about 1.0 mL) of the Hydrochloric Acid (HCl)
to the new substance and record your observations.

Observations:

Description of Baking Soda sample:

Description of Baking Soda reacting with 1.0 mL HCl:

Description of what happened to the lit wood splint in the beaker:

Description of the new substance after heating:

Description of the new substance reacting with 1.0 mL HCl:

Chemical Reaction of the baking soda and Hydrochloric Acid:

Data: (none)

Diagram:

Conclusion: _______________________________________________________

_________________________________________________________________

_________________________________________________________________

Questions:

1. How did adding the HCl to the new substance confirm that the baking soda had been changed?
2. The wood splint test you performed was to determine the presence of Carbon Dioxide (CO₂). Describe this test and what a positive
result would be.
3. List the five indicators of a chemical change and place a check mark next to the ones you observed in this lab.
4. What were the physical and chemical differences between the Baking
soda and the new substance?

Answers: