Physical and Chemical Properties

Physical and Chemical Properties
Purpose:
The Physical and Chemical Properties lab provides the opportunity to investigate the physical and chemical properties of pure chemical substances and analyze the experiment results.
Procedure:
In the beginning of the experiment, I filled two 24-well plates half way with the given chemicals and sucked up these chemicals into their labeled pipets for later use. Following this, I performed a number of steps on each of the four test tubes and recorded observations of the different substances including odor, color, reaction to heat, the effects on the red and blue litmus paper and HCI reactions.

Data Tables:

Data Table 1: Solubility or Reaction
Substance Name Color Odor Effect of Heat Cold H20 Hot H20 Litmus Test Dilute HCI Dilute NaOH
Mg Silvery, white Metallic Intense light N/A malleable Red to blue None None
Cu Reddish Metallic Dull glow N/A malleable, ductile Blue to red dissolve dissolve
Zn Pale gray Metallic N/A below 110*C N/A N/A none None None
MgO white ammonia N/A Creates Mg(OH)2 Creates Mg(OH)2 Red to blue None None
CuCO3 Dull white Odorless None Dissolves Dissolves Red to bleach Dissolve Dissolve
Cu(NO3)2 Blue crystals Odorless None Dissolve Dissolve Red to blue Dissolve Dissolve
NaCl None, crystals Odorless None Dissolve Dissolve Turns red Dissolve Dissolve

Observations:

As most of the observations are noted on the table above, it is a fair assumption that all of these substances went through some sort of change whether it was a chemical or physical change except for Zinc. This may be because I had dropped my Zinc sample and had a tough time retrieving the contents but never the less; it had very little to no reaction to the tests. Also, regarding the boiling point and melting point of different substances; some had no reaction at all.

Questions:

Did you observer any chemical changes in this experiment?

Yes, Litmus paper is an example of chemical solely and was effected by all the substances except for Zn.

What evidence did you use to decide that something was a chemical change?

Chemical compounds of the litmus paper reacted with the chemical compounds of the substance tested to create a new compound resulting in a change of color of the litmus paper. No evidence was visibly seen when MgO Mg(OH)2.

Give at least two examples of chemical changes you observed.

One example was the reaction on the litmus paper and the second example was Magnesium oxide’s change into Magnesium hydroxide when introduced to water.

Classify the following properties of sodium metal as physical or chemical

• Silver metallic color: Physical
• Turns gray in air: Physical
• Melts at 98oC: Physical
• Reacts explosively with chlorine gas: Chemical

Classify the following changes as physical or chemical

• Water freezes at 0oC: Physical
• Baking soda when combined with vinegar produces bubbles: Chemical
• Mothballs gradually disappear at room temperature: Physical
• Ice cubes in a freezer get smaller with time: Physical
• Baking soda loses mass as it is heated: Physical
• Tarnishing of silver: Chemical

F. How would you show that dissolving table salt is a physical change?

By boiling the water and using a distillation process to extract the pure salt. Once all water is retracted, you can see that the salt never went through a chemical change.

Conclusions:

By conducting this lab, it can be seen that physical and chemical changes are an everyday occurrence among many different substances. Using prepared lab techniques, we can make qualitative observations on the appearance, smell, and reactions of different substances. The Physical and Chemical Properties lab provides the opportunity to investigate the physical and chemical properties of pure chemical substances and analyze the experiment results within the guiding principles and techniques. By doing so, the following can be learned though the experiment: Chemical properties describe the tendencies of a substance to undergo chemical change and physical properties commonly used to characterize pure substances are color, odor, hardness, density, melting point, boiling point, and solubility in various solvents.