Lab 2 Write-Up Per: 3 Physical and Chemical Change Purpose: The purpose of this experiment was to observe and receive a stronger understanding of whether certain changes are physical changes or chemical changes. Procedure: See Attached Data and Observations: Table 2.1 Data Table for Part A Substance and Physical Color Odor Solubility in Effect of Formula State Water Magnet Sulfur, S Solid Powder Seems to be Seems to No solubility None Solid pale smell like yellow rotten eggs. Iron Fillings, Fe Rough solid Seems to be Seems to No solubility Attracted by powder Silver-Gray smell metal metallic with very light odor Sodium Hydrogen Crystalline Seems to be Seems to Soluble in None Carbonate, powder White have no water NaHCO3 odor Sodium Chloride, Crystalline Seems to be Seems to No solubility None NaCl solid powder White have no odor Sucrose, Solid Crystal Seems to be Seems to Soluble in None C12H22O11 Powder White have no water odor Sand, SiO2 Solid Grains Seems to be Seems to No solubility None Gray-Brown have no odor Magnesium, Mg Solid Strip Seems to be Seems to No solubility None Silver have no odor Table 2.2 Data Table for Parts B and C System Type of Change Evidence (Observations) Fe and S mixture Physical The two substances seem to be physically mixed but it could be easily reversed by using a magnet to attract iron and the color of each substance remain the same so the two mixtures keep their identity. NaCl and Sand Physical It is a physical change because the two substances mixture keep its identity because the color of each substance is the same and the mixture of these two substances could be reversed by using filtration because salt dissolves and sand doesn’t. Sand and Water Physical It is a physical change because sand is not mixture chemically mixed with water, instead it seems more physically mixed and it can be easily reversed by using filtration, which separates it from the water. The two substances also keep their identity because the colors of the two remain the same and nothing seems to change about them. Mg burned in air Chemical It is a chemical change because the magnesium ribbon changes its identity when it turned to a twisted solid that seemed to be white instead of what it used to be which was a silver strip. Mg reacted w/ Chemical It is a chemical change because the magnesium HC1 seemed to mix with the hydrochloric acid to form a liquid that seemed to be yellowish white. The magnesium change its identity when it change color and seemed to change temperatures from room temperature to hot. Burned Mg w/ Chemical It is a chemical change because the combustion HC1 product and hydrochloric acid seemed to mix to form a liquid that seemed to be clear water and a solid that seemed to be powder. Sucrose heated Chemical It is a chemical change because the sucrose changes to a color that seems to be brownish- black and the substance seems to take up more space in the test tube. There also seems to be a new smell to the substance that seems to sell like marshmallows. NaHCO3 and Chemical It is a chemical change because the sodium HC1 hydrogen carbonate mixes with the hydrochloric acid that causes it to fizz and the water seems to be clear. There is an acid and a base in this mixture that forms a new substance which makes it a chemical change. Fe and S heated Chemical It is a chemical change because the substance changes its identity when it seems to turn to a dark brown color that no longer has a response to the magnet. There also seems to be a new smell after burning that seems to smell like rotten eggs. Mixture Initial Mass Final Mass Sulfur (S) and Iron Fillings (Fe) 39.61 grams 39.59 grams Data Analysis: 1. How do you decide whether and observed property of matter is a physical or chemical property? Physical properties are the characteristics that can be observed without changing the substance into another substance. Chemical properties are the characteristics that can be observed when the substance undergoes a change in its composition. 2. What criteria are used to distinguish between a chemical change and physical change? A physical change is a reversible change that involves the substance keeping its identity while a chemical change is an irreversible change that involves the substance changing its identity to something new. 3. State in your own words the law of conservation of mass. The law of conservation of mass states that matter cannot be formed or destroyed but it can change its state to other forms in a closed system. Conclusion: This lab of physical and chemical changes has achieved its goal because it has helped me better understand the chemical and physical properties as well as the type of change of certain substances. It showed how physical changes are reversible changes that keep its identity while chemical changes are irreversible changes that changes to a different substance. Parts of the lab like the heating of the mixture of sulfur and iron fillings helped show me that this was a chemical change what was irreversible because you cannot return it to two separate substances again. Other parts such as the mixture of sand and water showed me that it was a physical change because the sand physically mixed with water and it could be reversed with filtration, which is the difference in solubility that separates the sand from the water. All in all, this lab helped my understanding of the differences in chemical and physical changes.