Identifying the Physical and Chemical Effects of Copper II Chloride on Aluminum

The Effect of Copper II Chloride on Aluminum

Background

Copper II chloride is a toxic, odorless, green-blue colored chemical (Iowa State) that is used in rat poison and is a by-product of the computer chip industry.

Purpose

The purpose is to become comfortable recognizing chemical versus physical changes; to practice describing chemical and physical properties; and to learn and practice different kinds of observations.

Hypothesis

If copper chloride is added to aluminum, then the reaction will result in Al + Cu + Cl .

Materials

-aluminum foil

-copper II chloride crystals

-two (2) beakers or other jars

-50 mL deionized water

-pipette

-microscope & slide

-thermometer

-paper towels

Procedure

1. Put on safety goggles, tie back long hair, and roll shirt sleeves.
2. Cut a 10cm x 10cm square of aluminum foil and lightly crumple into a ball.
3. Measure deionized water into the beaker. Transfer the crystals using a spoon to the water until dissolved. Measure the temperature of the water and record observations.
4. Place aluminum in beaker. If water is still grey, add more aluminum. When the reaction is finished, measure the temperature and record observations again.
5. Cut paper towels and fold to form a filter. Slowly pour mixture through filter into another beaker. Collect some mixture with the pipette and place on a glass slide. While it is evaporation, rinse the disposal beaker with water and safely dispose of ingredients.
6. Once the mixture has evaporated, observe with a microscope and record observations. Clean up any remaining waste.

Data Collection

Reactants Observations of Reaction

copper chloride + deionized water -some crystals dissolved

-water turns a dark green color, concentrated on the bottom of the jar

-some light green near surface

copper chloride + deionized water, stirred -crystals finish dissolving

-brilliant blue color

copper chloride mixture + aluminum foil -bubbles form on surface of foil

-begins smoking

-acrid smell

-dark red substance forms on foil

-water turns a dark blue

-aluminum becomes soft and pliable

-temperature reaches 80 degrees C

-water eventually turns a milky grey color

copper chloride mixture, evaporated -small white crystals

-‘cracked’ appearance

-thick white outer ring

Data Analysis

Because there were red particles leftover on the aluminum foil after the reaction, my partner and I believed this was copper, which appeared to support our original hypothesis. Ms Meloy verified this presence of copper when, during the flame test, the flame burnt a blue-green color.

Conclusion

All purposes of the lab were achieved. My partner and I practiced observing chemical and physical changes, described these changes, and practiced different kinds of observations (through weighing crystals, record temperature, and recording qualitative observations). The data both supported and failed to support our hypothesis, however. Copper was produced during the reaction, and was a product in our original guess for the reaction. However, if copper chloride and aluminum did react to form Al + Cu + Cl , chlorine gas would be a product as well; my partner and I failed to see any yellowish-green colored gas present during or after the reaction. We also knew the bubbles present in the water were not chlorine gas after Ms Meloy proved it was hydrogen gas during the “pop test”. There, the actual reaction was not Al + CuCl = Al + Cu + Cl₂, like we originally thought. Because the other two of the four given reactions included aluminum and copper bonding, which is impossible, the logical last reaction was Al + CuCl = Cu + AlCl .

Possible experimental design errors could include using different amounts of copper II chloride, exerting more/less force on the aluminum ball as it is crumpled, or not stirring the crystals and dissolving them completely. To improve the experiment, the mass of all copper chloride crystals should be standardized and the dimensions of the ball of aluminum measured and standardized, while the stirring of the water and crystals should be timed and standardized as well.

This information applies to life outside the classroom in that it is important to know certain facts so one can make educated guesses to predict outcomes. Knowledge from this experiment includes the information that two metals never bond; chlorine gas is a visible, colored gas that reacts with water to form hydrochloric acid; water provides activation energy for a reaction; and an equation does have to have equal amounts on either side of the equation, one can balance it by adding coefficients. This experiment also provided the opportunity to practice making informed conjectures based on the information at hand.