The Acids: Converting Copper Lab

Notes: Procedure:
• Copper powder before the heating is a fine brick-red powder substance
• After the two minutes being on the hot plate, the substance was charcoal and stiff with a slightly purple hue
• Then it was removed from the hot plate and broken up as much as possible with a spatula into a not as fine powder
- Then we placed the crucible back on the hot plate for 10 more minutes with the top ajar to let some oxygen in
• Every two minutes we removed the crucible from the hot plate and broke up the solid with a spatula as previously done
• After the first 2 minutes, it remained a powdery substance with more solid particles
- Instead of having a purplish hue it had a charcoal color
• After the next two minutes the substance remained the same
• After the next two minutes the substance remained the same
• Then we removed the crucible from the hot plate, placed it on the base of the ring-stand, and allowed its contents to cool to room temperature

Questions: Page 140:
1. Answers
a. Describe changes you observed as you heated the copper.
i. We observed color change and the formation of solid particles within the heated crucible. In the first stages of heating, the copper became charcoal in color with a slightly purple hue, and by the end of the heating cycle, the copper was completely charcoal in color.
b. Did the copper atoms remain in the crucible? Explain, using evidence from your observations.
i. Yes the copper did remain inside the crucible but there were slight powder stains on the sides of the crucible that changed color along with the rest of the powder.
2. Answers
a. Were the changes you observed physical changes or chemical changes?
i. As we observed, the copper oxidized; therefore, the changes were chemical changes.
b. What observational evidence leads you to that conclusion?
i. It is a chemical reaction because burning, or combustion, involves chemical reactions between the copper and the oxygen.
3. Answers
a. How did the mass of the crucible contents change after you heated the copper?
i. The mass of the contents did not change at all, they were exactly the same before and after heating
b. Explain why the mass of the crucible contents change in that manner.
i. Although we recognized that the mass of the crucible content should have increased after oxidization, it remained the same. This may be due to crushing the powder too fine, or because of not enough copper particles oxidizing.

Aggregated Data:

Average gain: 0.06g
Median gain: 0.06g