The first reaction with baking soda - Sample Essay
OBJECTIVES: 1. To observe the physical and chemical properties of several substances. 2. To decide whether certain observed changes are physical or chemical. 3. To experience several methods of separating mixtures. MATERIALS: 1. ring stand, ring, gauze 12. Bar Magnet 2. burner 13. Distilled water 3. stirring rod 14. Table sugar (sucrose) 4. magnesium ribbon 15. 100 mL beaker 5. Table salt (sodium chloride) 16. 250 mL beaker 6. spatula 17. sand 7. baking soda (sodium hydrogen carbonate) 18. evaporating dish 8. filter paper, funnel 19. vinegar 9. Silver Nitrate 20. test tube holder 10.
Iron and Sulphur 21. 3 test tubes/ rack 11. lab coat and goggles 22. 6 M hydrochloric acid PROCEDURES: A. The Physical Properties of Matter Obtain samples of the following compounds and record in your data section their physical states, colors and odors 9WAFT their odors to your nose-don’t inhale directly above the sample): Name Chemical Formula Table Salt NaCl Baking Soda NaHCO3 Sucrose C12H22O11 Sand SiO2 Magnesium Mg Vinegar HC2H3O2(aq) B. Physical and Chemical Changes 1. Approximately 20ml vinegar was obtained in a 150 mL beaker. One scoop of baking soda was tossed into the vinegar.
A burning splint was then quickly placed near the mouth of the beaker. Observations were recorded in the data section. 2. a. ) Approximately 40 ml 3M HCl (concentrated hydrochloric acid) was obtained in a test tube. b. ) A 2 cm sample of magnesium ribbon was placed into the test tube containing the hydrochloric acid. Observations were recorded in the data. 3. a. ) A small scoop of sucrose was placed into each of 2 test tubes. b. ) Distilled water was added to one of the tubes. The tube was flicked to mix as it was shown in class and observations were recorded in the data section. c.
) The second test tube containing sucrose was placed into a test tube holder and it was heated gently in a burner flame. d. ) The tube was observed carefully for changes. The tube was periodically removed from the flame and it was checked (waft) for any odor generated. e. ) The residue was heated in the test tube more vigorously for 1-2 minutes. The tube was removed from the flame and placed in a test tube rack to cool. 4. a. ) Approximately 1-2g sand and 1-2g table salt were combined into a dry, clean 100mL beaker. 30mL of tap water was added and the mixture was stirred with a glass rod.
Observations were recorded. b. ) The mixture was filtered as shown in class. A piece of filter paper was folded in quarters. The paper was then opened to form a cone with one thickness of paper on one side and three thicknesses on the other. The filter paper was placed in a glass funnel and the funnel was then placed in a ring support attached to a ring stand. c. ) A 150mL beaker was placed below the funnel and the salt/sand/water mixture was poured into the funnel. The liquid that passed through was called the filtrate. d. ) 10mL of the filtrate was poured into an evaporating dish.
The dish was set on a square of wire gauze supported by an iron ring attached to the ring stand. Using a gas burner and keeping the face away from the evaporating liquid, the dish was heated gently until the filtrate completely evaporated. e. ) The dish was allowed to cool. While the dish was cooling, the filter paper was removed from the funnel and both the dry residue in the evaporating dish and the wet residue on the filter paper were examined. Observations were recorded. The filter paper was then discarded into the waste basket. 5. 2 to 3 drops of silver nitrate solution were placed in each separate piece of paper.
One piece of the paper was placed in a locker (dark) and the other was exposed in the sunlight. After 5 minutes, the two pieces of paper were observed and data was recorded. 6. 5g of iron filings and 8g of sulphur powder were placed in a mortar. The elements were grinded together with a pestle. The result substance was spread on a piece of paper and it was observed. A bar magnet was placed over the paper and observed as well. OBSERVATIONS, RESULTS, DATA:
Name Chemical Formula Physical State Color Odor Table Salt NaCl Solid white Mild Baking Soda NaHCO3 solid white Mild Sucrose C12H22O11solid white Mild sweet Sand SiO2 solid brown Odorless Magnesium Mg solid Dark grey Odorless Vinegar HC2H3O2(aq) liquid Clear(transparent) Pungent PHYSICAL PROPERTIES OF OBSERVED COMPOUNDS.
Mixture Observations Baking Soda and Vinegar – mixture fizzed – white foam was produced – burning splint at the top of the beaker out after about a minute CHANGES OBSERVED IN BAKING SODA/VINEGAR MIXTURE WITH LIGHTED SPLINT Compounds Observations Hydrochloric acid (HCl) and Magnesium (Mg) – mixture fizzed – magnesium strip turned silver colored – magnesium strip dissolved/disappeared – white gas evolved.
THE REACTION OF HYDROCHLORIC ACID AND MAGNESIUM Sucrose Test Tube # Observations #1- Water and Sucrose Solution -sucrose particles dissolved in water. – few sucrose particle visible after stir -transparent solution formed. #2- Heated Sucrose -sucrose began to melt -turned light brown color -sweet odor detected -after 1-2 mins of heating, sucrose bubbled, turned black color.