Name ______Date ______Period _____
Copper Chemical Reaction Lab
______ ______ ____________ ______ ______
Problem
What type of reaction will occur when copper is heated?
Background Information
Chemical reactions can be broken into 5 categories: synthesis, decomposition, single displacement, double displacement, and combustion. Each type of reaction is classified by how the reactants and products break apart, come together and/or atoms rearrange.
When a chemical reaction is done, it is usually done with more of one reactant than needed. In this case, the reaction is said to “be done with an excess of substance A.”
In this investigation, you will use copper, which in this experiment has an oxidation number of 2+.
Pre-lab questions to think about:
How will you know when/if a chemical reaction takes place?
What is the law of conservation of mass?
What other materials will be present as part of the system?
Materials
Gauze stand Copper powder/granules Tongs Triple-beam balance
Alcohol burner Evaporating Dish Safety goggles Calculator
Procedure
1. Find an appropriate pair of goggles and wear them until the conclusion of the lab.
2. Gather all materials except the copper powder/granules.
3. Set up the materials exactly as shown on the front demo table.
4. Place the evaporating dish on the balance and find its mass to the nearest tenth of a gram. Record the mass in (a).
5. Obtain some copper powder/granules from your teacher and add it to the evaporating dish. Take the mass now and record in (b). Make and record observations of copper.
6. Determine the mass of only the copper powder and record in (c).
7. Place the evaporating dish containing the copper on the wire gauze stand. Make sure the copper is in a thin layer on the bottom of the dish.
8. Raise your hand to have the teacher light your burner. Heat the dish for 10 minutes.
9. Make observations of the reaction as it is taking place.
10. Raise your hand to have your teacher put out your flame. Allow the dish to cool for 8-10 minutes.
11. Use the tongs to place the evaporating dish on the balance and find the mass. Record this mass in (d).
12. Determine the mass of just the new substance and record in (e).
13. Return all materials to where you picked them up from. Leave the new substance in the evaporating dish.
14. Wash your hands with soap and water and return to your seat.
Quantitative (number-based) Observations – be sure to include units
a. Mass of empty evaporating dish ______
b. Mass of evaporating dish + copper ______
c. Mass of copper ______
d. Mass of evaporating dish + new substance after heating ______
e. Mass of new substance ______
Qualitative (non-number-based) Observations – use additional paper if necessary
Before rxn –
During rxn –
After rxn -
Draw the set-up of the lab equipment (with labels) and include in your lab report.
Analysis/Conclusions Questions (include this information in your conclusion).
1. What did you observe as a result of heating the copper powder/granules that might indicate that a chemical reaction took place?
2. What substance was “in excess” in this lab? What were the reactants? What was the state of each?
3. Why was it necessary to have the copper in a thin layer in the evaporating dish?
4. What was the change in mass when the copper powder reacted with the other substance? Was this change an increase or decrease in mass?
5. Explain why there was a change in mass as a result of heating the copper. What new substance was formed?
6. What classification of reaction was this? (see 21.3) How do you know?
7. Write a balanced chemical equation for the reaction that took place. See table 1 on p 635.