Chemical and Physical Changes Lab Report Essays

Chemical and Physical Changes Lab Report Essays Chemical and Physical Changes Lab Report Paper Chemical and Physical Changes Lab Report Paper Because the glassware is glass, they may break and as such must be handled gently. All glassware should be inspected for cracks before starting the lab. Ill. Pre-Lab Questions- 1 . Identify the following as either chemical or physical changes: A. Striking a match- Chemical B. Food Spoiling- Chemical C. Breaking a Glass- Physical D. Mowing the Grass- Physical E. Leaves Decaying- Chemical F. Boiling Water- Physical 2. In your own words, state the Law of Conservation of Mass: The Law of the Conservation of Matter says the matter can be neither created nor destroyed. . List the indicators of a chemical change: Chemical change can be illustrated in many forms such as rust, decay, light Ewing produced, heat being given off or cold being given off, and color change. These are simply a few and are not all of them. 4. Identify each as an element, compound, or mixture: A. Air- Compound B. Sulfur- Element C. Hydrogen Gas- Element D. Salad- Mixture E. Water- Compound F. Sodium Bicarbonate- Compo und G. Fruit Punch- Compound H. Sodium Chloride (table salt)- Compound IV. Procedure- Experiment 1- Combine a few iron filings along with sulfur powder on an unused piece of paper. Mix the samples well with a scoopful. Examine the mixture with a magnifying lass and record your observation. Next, move the magnet under the mixture and reexamine it with a magnifying glass once again and record the observations. Discard the sample. Experiment 2- Fill a small beaker half way with cold water. Obtain a test tube with warm bath water and add the warm bath water with the cold water in the beaker. Record all observations. Clean up by simply removing the solid from the water and placing it in the trash can and dump the water down the sink. Experiment 3- Place a piece of magnesium in a clean, dry test tube. Next, add 10 drops of MM HCI. Record observations. Carefully touch the bottom of the test tube to check for the change in temperatures. Flush contents down the sink with plenty of water. Experiment 4- Transfer small amounts of sodium bicarbonate into a clean, dry test tube. Add 10 drops of MM HCI individually. Touch the bottom of the test tube and record all observations. Wash all the leftovers down the sink. Experiment 5- Mix 10 drops of barium chloride solution in a test tube with sodium sulfate solution. Record all observations in the data table and then pour down the sink. Experiment 6- Mix a small scoop of sodium chloride with 2 ml of water in a test tube. Record all observations and wash down the sink. V. Data and Observations- Experiment # Mass and Observations Chemical or Physical? When the magnet was held under the piece of paper, the iron stood up and followed the magnet physical 2 The warm water became a solid when added to the cold water physical 3 When the MM HCI was added, the liquids began to bubble and heat up, which is exothermic chemical 4 When the MM HCI was added, the liquids began to bubble once again and the liquids cooled, which was endothermic chemical When the barium chloride was added, the color changed and the consistency changed to a more milky consistency physical 6 When the small scoop of sodium chloride was added to the water, nothing could be observed as happening physical VI. Calculations- VII. Post Lab Questions- 1. In which lab did you observe a precipitate? A precipitate was observed in experiment number 2. 2. In which did you observe energy change? An energy change was observed in experiment number 1 when potential energy changed to mechanical energy. 3. In which did you observe a color change? A color was observed in experiment was observed in experiment number 5 when it became a milky color. 4. In which did you observe the formation of a gas? None of the experiments performed by my group resulted in the formation of any gases of any sort. VIII. Conclusion- The purpose of this lab was to identify what a chemical change and what a physical change is. A chemical change is when bonds are broken and new ones are forced to form. Some indicators are a change are exothermic (heats up), endothermic (cools off), precipitate (solid forms), and color change. In he first experiment when the magnet was under the sheet of paper with the iron filings, the iron filings stood up on their end and followed the magnet around, changing from potential energy into mechanical energy. In the second experiment performed, a precipitate formed, a solid was formed out of the warm water when it was added to the cold water. In experiment three, an exothermic change occurred when the magnesium and MM WHQL where combined, resulting in bubbling of the two and then the test tube heating up. Then in experiment four, an endothermic change occurred when the sodium bicarbonate and MM HCI ere combined in the test tube and the test tube cooled down. In experiment five, there was a color change when the barium chlorine and sodium sulfate were combined resulting in a new milky color which also now had a milky consistency. In the sixth experiment, as far as I could tell, nothing happened in the sixth experiment. IX. Error Analysis- The only possible error I can see is if my group made an error of some sort of error in experiment number 6 when nothing happened, and it just seems like something should have happened in the experiment.