Class PolicyRESPECT: • No talking during notes session.• In discussion sessions, let one person talk at one

time. No talking out of turn.• If you borrow something, put it back.• Return items in the same or better condition.• Hall passes-Never during notes session.

– One student at a time-• 5 min. max for bathroom• 1 min. for water fountain

Lab-0 Results(Observations of Silver nitrate and copper)

• Copper wire, Cu(s) is added to a solution of Silver nitrate solution, AgNO3 (aq).

Copper wire and silver nitrate

Copper, Cu(s)

Solution ofSilver nitrate

AgNO3 (aq)

Cu and AgNO3 immediately upon mixing

Videoclip

After 5 minutes

Observations

1. A grayish or silver-colored crystal immediately begins to form on the surface of the copper metal.

2. The liquid turns from colorless to blue.

After 10 minutes

Observations

3. The solid crystals get thicker as time passes.

It looks like a pipe cleaner or a fuzzy caterpillar.

After tapping the test tube on the test tube rack

Additional Observations

4. After tapping the test tube on the table the gray solid fell to the bottom of the test tube.

5. The copper wire is thinner than before.

6. The copper wire changes color again and gray/silvery-white crystals began to form again on the remaining wire.

Hypothesis for this observation:

• A grayish or silver-colored crystals must be the dissolved silver metal coming out of the silver nitrate solution as a solid.

Chemical representation is: Ag+1(aq) Ag(s)

Observation 1: A grayish or silver-colored residue immediately begins to form on the surface of the copper metal.

Note: (aq) = aqueous or “dissolved in water”(s) = “solid”

Hypothesis for this observation:

• A grayish or silver-colored crystals must be the dissolved silver metal coming out of the silver nitrate solution as a solid.

Observation 1: A grayish or silver-colored residue immediately begins to form on the surface of the copper metal.

Experimental Procedures:1. Add copper wire to a solution that still contains the

NO3 but is with another metal like gold.

2. Chemical representation: Cu(s) + AuNO3(aq) ??If same crystals form then Hypothesis is NOT valid.

If new crystals form then Hypothesis IS valid and can be tested with further experimentation.

Hypothesis for this observation:

• The blue color of the liquid is a result of copper metal dissolving into the liquid.

Chemical representation is: Cu (s) Cu +2(aq)

Observation 2: The liquid turns from colorless to blue.

Note: (aq) = aqueous or “dissolved in water”(s) = “solid”

Prediction: Copper solutions will have a blue color.

Hypothesis for this observation:

• The blue color of the liquid is a result of copper metal dissolving into the liquid.

Observation 2: The liquid turns from colorless to blue.

Prediction: Copper solutions will have a blue color.

Experimental Procedures:1. Add an iron, Fe, wire to the same solution of silver

nitrate.

2. Chemical representation: Fe(s) + AgNO3(aq) ??If same color is produced then Hypothesis is NOT valid.

If the color is different then Hypothesis IS valid and can be tested with further experimentation.

Hypothesis for this observation:

• The silver metal coming out of the silver nitrate solution as solid crystals continue to accumulate until all the dissolved silver in the original solution is used up.

Chemical representation is: Ag+1(aq) Ag(s)

Observation 3-6: The solid crystals get thicker as time passes and continue to thicken even when knocked off the wire.

Note: (aq) = aqueous or “dissolved in water”(s) = “solid”

Hypothesis for this observation:

• The silver metal coming out of the silver nitrate solution as solid crystals continue to accumulate until all the dissolved silver in the original solution is used up.

Observation 3-6: The solid crystals get thicker as time passes and continue to thicken even when knocked off the wire.

Experimental Procedures:1. Try using a lower concentration of silver nitrate solution with the

same procedures.

2. If there is less silver in the solution, there should be a smaller amount of crystals that form.

If same amount of crystals form then Hypothesis is NOT valid.

If less crystals form then Hypothesis IS valid and can be test with further

experimentation.

Video Clip (Soda)

• State benchmark-

Explain the political, societal, economic and environmental impact of chemical products and technologies.