Physical and Chemical Reactions

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Physical and Chemical Reactions
Lab #4
Alesa Cannon

Objective: To investigate the physical and chemical properties of a pure chemical substance.

Procedure:
1. Half-fill one well of a 24-well plate with 6 M HCl and half-fill a second well of the 24-well plate with 6 M NaOH. Suck up these chemicals into their labeled pipets for later use. 2. Perform the following steps on each of the substances to be tested. Complete all tests of one substance and record your observations before proceeding to the next. a. Place 4 small test tubes into wells of the 24-well plate. b. Place small amounts of the substance to be tested in each of the four micro test tubes. 3. First test tube:

a. Examine and record color and odor.
b. Light the burner fuel wick. Grasp the test tube with the holder and heat the sample by slowly moving it just above the flame, as displayed in Figure 1. Observe the effect of heat on the substance. Note the evolution of any gases.

c. Allow the test tube to cool before storing or the well plate plastic may melt. 4. Second test tube:
a. Add enough cold water to 1/4 fill the test tube above the sample material. Stir with the glass stirring rod. Observe the solubility of the substance in cold water. b. Light the burner fuel wick. Grasp the test tube with the holder and heat the sample by slowly moving it just above the flame, making sure the flame is directed toward the top of the water and the test tube’s open end is not pointed at anyone. Gently heat the water just to boiling. Observe the solubility in hot water.

c. Tear off approximately 1/2-cm pieces of both red and blue litmus paper. d. Allow the solution to cool, and using the glass stirring rod, transfer a drop of the solution onto a piece of litmus paper. Record the results. Clean the stirring rod. 5. Third test tube:

a. Add a few pipet drops of HCl (hydrochloric acid) to the sample and stir. NOTE: Use the test tube holder\clamp as some reactions are exothermic, i.e. the test tube may get very hot. Record any apparent reaction or solubility. Clean the stirring rod. 6. Fourth test tube: Add a few pipet drops of NaOH (sodium hydroxide) to the sample. Stir. Record any apparent reaction or solubility. Clean the stirring rod. 7. Thoroughly clean and dry all 4 test tubes. Repeat Steps 2 though 6 with the next substance.

Observations and Experimental Data:

Substance: Mg
Color: Silver
Odor: Slighty
Effect of Heat: Particles moved, bubbles flowing up to top
Solub. or Reaction w/cold H2O: No reaction
Solub. or Reaction w/hot H2O: Bubbles produced from the gas
Litmus test: Red turned blue and blue had no change
Dilute HCl: Sizzle, steams, heat output
Dilute NaOH: Gas was formed.

Substance: Cu
Color: Redish Brown
Odor: None
Effect of Heat: Became darker, almost purple like.
Solub. or Reaction w/cold H2O: No reaction
Solub. or Reaction w/hot H2O: No reaction
Litmus test: No reaction on red or blue.
Dilute HCl: Solution turned yellowish, but no actual reaction on copper Dilute NaOH: No reaction

Substance: Zn
Color: Silver
Odor: None
Effect of Heat: None
Solub. or Reaction w/cold H2O:None
Solub. or Reaction w/hot H2O: None
Litmus test: Blue turned white. Red had no reaction.
Dilute HCl: Bubbles up and fumes form, the zinc became darker in color. Dilute NaOH: None

Substance: MgO
Color: White
Odor: Yes
Effect of Heat: None
Solub. or Reaction w/cold H2O: Dissolved water turned white. Solub. or Reaction w/hot H2O: MgO separated from water.
Litmus test: Red turned blue and blue had no reaction
Dilute HCl: Fizzes and substance turns yellowish while bubbling the back to white. Dilute NaOH: Dissolves and substance became a bit thick

Substance: CuCO3
Color: Green
Odor: Yes
Effect of Heat: Turned into black powder
Solub. or Reaction w/cold H2O: No reaction.
Solub. or Reaction w/hot H2O: No reaction
Litmus test: No change on blue or red.
Dilute HCl: Bubbles up, does not dissolve, solution turns green Dilute NaOH: Turns...
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