Experiment 1 Exercise 1 Data Table 1 Data Table 1: Observations Of Chemical Reactions With Aluminium Foil AgNO3 CuSO4 CaCl2 Pb(NO3)2 Start Time Colorless Blue White Colorless Grayish White Grayish White Grayish White Grayish White Initial Appearance Of Chemical Initial Appearance Of Foil Observations After 5 Minutes Observations After 3 Hours Appearance Of
The Correct Answer and Explanation is :
To fully analyze the data and provide a comprehensive response, I’ll break down the chemical reactions between aluminum foil and the salts you provided: AgNO₃ (silver nitrate), CuSO₄ (copper sulfate), CaCl₂ (calcium chloride), and Pb(NO₃)₂ (lead nitrate). Below is a general approach to explaining the experiment, based on typical reactions involving aluminum foil.
Experiment Overview:
The experiment involves placing aluminum foil in various salt solutions, and observing changes over time. The key variables being observed are the initial appearance of the solutions, and how the aluminum foil and the solutions react over time (5 minutes and 3 hours).
Hypothesis:
Aluminum reacts with certain metal salts, leading to the displacement of metal cations from the solution. This is known as a redox reaction, where the aluminum undergoes oxidation (loses electrons), and the metal cation is reduced (gains electrons).
Observations:
- AgNO₃ (Silver Nitrate Solution): When aluminum foil is placed in silver nitrate solution, a colorless solution starts to develop solid silver as a precipitate after some time, due to the reduction of silver ions. This is typically observed as a grayish-white deposit forming on the aluminum foil.
- CuSO₄ (Copper Sulfate Solution): In copper sulfate solution, the blue solution changes as aluminum reacts with the copper ions. Aluminum displaces copper, and the solution turns colorless while the aluminum foil develops a reddish-brown copper coating over time.
- CaCl₂ (Calcium Chloride Solution): Calcium chloride does not significantly react with aluminum under normal conditions, leading to no noticeable color change or visible reaction after both 5 minutes and 3 hours. The foil may remain unchanged with no notable formation of any precipitate.
- Pb(NO₃)₂ (Lead Nitrate Solution): Lead nitrate, similar to silver nitrate, can undergo a reaction with aluminum, leading to a grayish-white precipitate of lead after a while. This is caused by aluminum displacing the lead ions from solution, forming solid lead metal.
Explanation:
Aluminum is a reactive metal that readily displaces other metals from their compounds, especially when the metal cations are in a higher oxidation state. In the cases of silver, copper, and lead, aluminum has a greater affinity for electrons and thus reduces the metal cations, displacing them from the solution. This is why we observe the formation of solid metals (silver, copper, and lead) on the aluminum foil.
In the case of calcium chloride, calcium is already in its lowest oxidation state (Ca²⁺), and thus does not undergo a similar displacement reaction with aluminum.
Conclusion:
This experiment demonstrates the reactivity of aluminum in different salt solutions and its ability to displace metal ions from their compounds, leading to the formation of solid metals.