Packet for Cu lab, naming and writing formulas, reaction types and ...

Copper lab
Introduction: Chemical reactions are often accompanied by a formation of a precipitate, production of gas (known as
evolution of gas in chemistry), change in color, or a pronounced temperature change. You will observe all these evidences
for chemical change in a series of laboratory experiments that will span several days. You will begin with the copper and end
with the same element, but on the way you will make it react with different compounds. You will also learn to write chemical
formulas that show the changes copper undergoes during these reactions, several laboratory techniques and terminology.
Purpose:
• To recognize that production of gas, change in color, formation of a precipitate, or the evolution of heat are often
associated with chemical changes.
• To study changes of copper as it goes through a cycle of several reactions.
• To practice writing proper chemical formulas, using the reactions of copper as examples.
Be very careful when working in the lab and wear goggles at all times, since you will be using dangerous chemicals.
Your teacher will show you how to dispense the nitric acid (HNO3) at the extraction hood. Take this opportunity to record
HNO3 appearance in your observations section.
Changing Cu to Cu(NO3)
1. Wear goggles and closed toe shoes
2. Go to a weighting station, tare the plastic container and take approximately 1.5 g of copper. Place the Cu in a 400 ml
beaker
Write here the exact amount of copper you obtained:______________________________
3. Record Copper’s appearance in your observation section
4. Go to the extraction hood where you will carefully add 20 ml of nitric acid to the copper according to your teacher’s
instructions
5. Place a watch glass on top
6. Take your beaker to your lab table and place it over white paper. Write your observations of the reaction.
Observations
Observations before reaction
• Cu:
Observations during and after the reaction
• During reaction:
• HNO3:
• After reaction:
You will continue to work with the copper nitrate in another class. Answer the following questions:
A. What evidence of chemical change did you observe? ________________________________________________
____________________________________________________________________________________________
B. Look at your classmates’ beakers after the reaction. Describe any significant difference or similarities: ____________
_____________________________________________________________________________________________
C. If the same happened in all of the beakers, why does Cu always form the same compound when mixed with HNO3?
_____________________________________________________________________________________________