THE MAKING OF SILVERANDFALLING SNOW

PART I:

The MAKING OF SILVER

PURPOSE:

  • To observesolutes dissolving and precipitating out (which means to leave or fall out) of a solution as the result of a chemical reaction.
  • To see if the concentration of the solution has an affect on how much solute is produced (precipitates out) during a reaction.
    The Rxn: 2AgNO3 + Cu Cu(NO3)2 + 2Ag

MATERIALS:

GOGGLES, 2 test tubes, test tube rack, and graduated cylinder.

CHEMICALS:

AgNO3 (Silver Nitrate), Distilled H2O, and copper wire.

PROCEDURES:

  1. MAKE SURE YOUR GOGGLES ARE ON YOUR FACE. Ask someone at your table if you are not sure.
  2. TRY NOT TO GET ANY SILVER NITRATE ON YOUR SKIN. IT WILL TURN IT BLACK, BUT DOES NOT CAUSE MUCH HARM OTHER THAN THAT. IF YOU DO GET IT ON YOU, WASH YOU SKIN FOR AT LEAST 30 SECONDS.
  3. Get 10 ml of silver nitratesolution (AgNO3) and pour into first test tube.
  4. For the second test tube get 1 ml of silver nitrate (AgNO3) and 9 ml ofDistilled Water(NOT tap water) (for a total of 10 ml). Pour solution into second test tube.
  5. Take two pieces of copper wire back to your table.
  6. Place one piece of wire in each test tube and watch what happens. Be patient.
  7. Let the reaction proceed for at least 10 minutes without moving the test tubes.
  8. Answer the questions that follow (start Part II before you do this).
  9. Clean up after you have answered the questions. Put solution in the collection container labeled AgNO3(including the wire).

POST LAB QUESTIONS: (*Use your notes and Vocab definitions for help)

  1. What is happening to the copper wire?What color is the solution turning (it will have a slight color at the end of 10 minutes)?
  2. What metal is collecting on the copper wire? (Hint: look at Rxn equation above)What metal is being dissolved into the solution?
  3. This type of reaction is an example of a/an (synthesis, decomposition, single replacement or double replacement). Explain which one it is and how you know.
  4. Which test tube(#1 or #2) has the most metal collecting on the copper wire? Why?
  5. How could I make the reaction proceed or go faster? List at least two ways.
  6. Sketch a picture of the experiment and a 2 sentence explanation into your notebook.

PART II:

MAKING FALLING SNOW

PURPOSE:

  • To add a solute to a solvent and determine if the solute is soluble in the solution.
  • To determine if you have created an unsaturated or saturated solution.

MATERIALS:

GOGGLES, glass bottle, and black top

CHEMICALS:

Boric Acid & H2O (Tap Water)

PROCEDURES:

  1. PUT YOUR GOGGLES ON AND KEEP THEM ON UNTIL YOUR TABLE IS DONE AND YOU HAVE FINISHED CLEANING UP YOUR TABLE AND WASHED YOUR HANDS.
  2. Get boric acid from Mr. Mathot at the chemical table.
  3. *NOTICE* – THE CRYSTALS COMPLETELY COVER THE BOTTOM OF THE BOTTLE.
  4. Fill glass container almost to the top with water. BE CAREFUL NOT TO OVER FILL AND GET THE ACID SOLUTION ON YOUR HANDS. WASH HANDS THOROUGHLY WITH WATER FOR AT LEAST 30 SECONDS IF YOU SPILL ACID ON YOUR HANDS.
  5. Tightly screw black top on bottle. DO NOT OVER TIGHTEN.
  6. Shake the glass container to mix the crystals and water (15 secondsonly). Be careful that the bottle does not leak.
  7. Observe solution while turning it upside down and right side up and gently shake it.
  8. Answer the questions that follow.
    *Note – No chemical reaction occurred in the mixing of boric acid with water.
  9. Cleanupafteryou answer the questions. Pour boric acid solution into labeled collection container, NOT down the sink. DO NOT DRINK (especially male students).

POST LAB QUESTIONS:(*Use your notes and Vocab definitions for help)

  1. What was the solvent? What was the solute?
  2. Did the boric acid mix with the water? Explain.
  3. Is the boric acid soluble in water? In other words did any of it dissolve? Explain.
  4. If you added more boric acid, what would you see happen? Why?
  5. What could you have done to make the boric acid dissolve better (list at least 2 ways)?
  6. Since not all the boric acid was able to dissolve, we would say the solution is ______(Chem. Rxn Vocab #3). That is why some solute was still on the bottom.
  7. How would you make this solution unsaturated (list at least 2 ways)?
  8. Sketch a picture of the experiment and a 2 sentence explanation into your notebook.

10/14/2018THE MAKING OF SILVER AND FALLING SNOW