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Abstract: This lab assignment is to observe certain substances and observe its physical and chemical changes in different environmental conditions. We first observed its physical properties, such as physical state and color and recorded it on paper. Then we did different types of experiments on some of the substances and observed the chemical changes. Some of the chemical changes where endothermic, exothermic, changes in color and changing of its physical state. We recorded the observations.
Introduction: The purpose of this experiment is to observe and record the physical properties and the chemical changes and to decide whether the changes were physical or chemical. We were given seven different substances. They include Sulfur, Iron, NaHCO3, NaCl, Sand, Magnesium, and C12H22O11. We recorded the physical properties of these substances. Physical properties include odor, color, density, solubility, boiling point and melting point. Physical properties can be used to describe and identify substances because they do not change in composition. After we recorded the physical properties, we experimented with certain substances and recorded the chemical changes.
Materials and Methods:
Safety Goggles Test tubes
Test tube holder (rack) Gas burner
Ring stand Utility clamp
Dropper pipet Crucible tong
A. The Physical Properties of Matter
1. Obtain seven small sheets of paper. Label each with the name of one of the following substances: magnesium, sulfur, iron, sodium bicarbonate, sodium chloride, sucrose, and sand. Using forceps, obtain two pieces of magnesium ribbon, one five-cm long and one 1-cm long, and place them on the appropriately labeled sheet of paper. Using a clean spatula, transfer a pea-sized sample of each of the other substances to the appropriately labeled sheet.
2. Examine each substance carefully. Use the magnifying glass.
3. Test the effects of a magnet on each substance by passing the magnet under the sheet of paper. Do not dip the magnet directly into the material. Record your observations.
4. Test the solubility of each substance in water by adding a small amount of each sample to 3 mL of water in separate small test tubes. Mix each sample well by stirring it. Record your observations. Save the magnesium ribbon, and the solid samples remaining on the labled sheets of paper. The liquid contents of the test tubes may be washed into the sink. The solids remaining in the test tubes should be placed in the chemical waste container.
B. Causing a Physical or Chemical Change
5. Combine the remaining samples of iron filings and sulfur on a clean piece of paper. Mix the samples thoroughly using a spatula. Examine the mixture with a magnifying glass. Record your observations.
6. Combine the remaining samples of sodium chloride and sand on a clean piece of paper. Examine the mixture and test its effect of a magnet. Record you observations. Transfer the salt-sand mixture to a clean beaker and add 30mL of water. Stir well. Record your observations. Now, filter the mixture. To do this, get a filter paper and fold it into a cone and place it in the funnel. Place a beaker under the funnel and pour the mixture into the funnel. Record your observations. Take the filtered mixture and place on top of a heater. The water should boil and evaporate. When it is evaporated completely record your observations.
7. A supervisor should burn the Magnesium ribbon. With a lighter, light the ribbon. The ribbon will ignite. Place the finished product on a dish and observe and record.
8. Take the other one-cm strip of Magnesium ribbon and put it in a tube. Add ten drops of hydrochloric acid. Record your observations including temperature.
9. Place the sucrose in a test tube and heat it. Observe the tube and record any changes.
10. Add five drops of hydrochloric acid to the sodium bicarbonate in a test tube. Record your observations and temperature.
Data and Results:
Table 12-1 Observations
Reaction Observation Reaction type
Sulfur Powder-like Yellow
Iron Hard solid Brown
NaHCO3 Powder Pale - white
NaCl Diamond shaped Clear - white
Mg Flexible, thin Silver
Sand Hard, diff. Shapes Varies from Brown - Red
C12H22O11 Hard Yellowish white
System Observation Chemical RxN?
Fe and S mixture - tested w/magnet Fe stays solid, but leaves brown stains on the yellow S. Iron leaves from S when magnet is placed, but the stain stays.
NaCl and Sand mixture - mix w/water Salt dissolves and sand remains in water. No
- filtered Salt water goes trough, but sand is collected. The salt water looks oily. No
- filtrate allowed to evaporate The salt water turns into crystals. Salt remains and water is evaporated. No
Mg -burned in air Mg burns and bright white light is given off. The
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Chemistry, Matter, Chemical elements, Dietary minerals, Reducing agents, Food additives, Chlorides, Magnesium, Chemical substance, Physical change, Hydrochloric acid, Hydrogen chloride
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