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LAB 2:Physical and Chemical Change

Abstract: This investigation explores the criteria used to distinguish between physical andchemical changes in matter.

Chris BrownJanuary 26, 2007 Lab Partner: Beverly Howard



Introduction: Many of the properties of matter and the changes it undergoes can be easilyobserved. Physical properties, like color and solubility, describe its appearance and how it

changes physically. Chemical properties, like flammability, describe how substance react.Physical changes involve only a change of state or size. Chemical changes always produce new

substances. In this experiment, substances will be observed to determine their physical

properties, and will be tested to observe both physical and chemical changes.

Procedure: In Part A, I observed the physical properties of seven substances: sulfur, iron,sodium hydrogen carbonate, sodium chloride, sucrose, sand and magnesium. These properties

were state, color, odor, solubility in water and magnetism.In Part B, I mixed iron and sulfur to see how it changed. I mixed sodium chloride and

sand in the same manner. This second mixture was then mixed with water and filtered, and thefiltrate was evaporated until dryness. Magnesium was burned and then mixed with hydrochloric

acid. Unburned magnesium was also mixed with hydrochloric acid. I heated sucrose until onlyresidue remained. Finally, I mixed sodium hydrogen carbonate with hydrochloric acid.

In Part C, the instructor heated a mixture of iron and sulfur to see how the mass wouldchange after a chemical reaction.

Data and Observations:

Substance

and formula

Physical

state

Color Odor Solubility

in water

Effect of

magnet

Sulfur, S Blah blah Blah blah Blah blah Blah blah Blah blah

Iron filing,

Fe

Blah blah Blah blah Blah blah Blah blah Blah blah

Sodium

hydrogen

carbonate,

NaHCO3


Sodium

chloride,

NaCl


Sucrose,

C12H22O11


Sand, SiO2 Blah blah Blah blah Blah blah Blah blah Blah blah

Magnesium,

Mg


The trends I see are that all were solids, most were non-magnetic, most did not have an odor, and

almost half of them were soluble in water.



System Observations

Fe and S mixture

-tested with magnet

yada yada yada

NaCl and sand mixture

-mixed with water

-filtered-filtrate allowed to evaporate

yada yada yada

Mg

-burned in air

yada yada yada

Mg

-reacted with 6M HCl

yada yada yada

Combustion product


yada yada yada

C12H22O11

-heated

yada yada yada

NaHCO3


yada yada yada

Fe and S mixture

-heated

Initial mass

Final mass

yada yada yada

What I notice is that simply mixing two solids does not produce a chemical change, but heatingor burning substances and mixing things with hydrochloric acid seem to cause a chemical

change.

Calculations: (There were no calculations in this experiment)

Conclusion: In conclusion, I found that the substances that I observed varied greatly in their physical properties. Some dissolved in water and some didn’t, most were not magnetic and most

did not have a noticeable odor. All were solid at room temperature. This experiment showedclearly the difference between physical and chemical changes that we were studying. When

items like iron and sulfur were mixed together, although they looked different, they each kepttheir own properties and could be separated easily with a magnet. This was obviously just a

physical change. On the other hand, when the white sugar was heated, it turned into a black,insoluble product, which clearly showed a chemical change. After completing this experiment, I

understand more clearly now what the difference between a physical and chemical change is.

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