PDF fillable: https://youtu.be/ERtd38uXCUg | Chemistry

https://youtu.be/ERtd38uXCUg ChemicalChangesVirtualLabdatacollectionandanalysis.docx 9 Physical and Chemical Changes Virtual Lab DATA COLLECTION: Be as descriptive and detailed as possible and include physical state, color, opacity, etc. in your observations!!! Watch the video linked in Falcon Online Content for these observations! Chemicals Reacted Appearance of Chemicals Before Mixing Observations After Chemicals Reacted, especially what changed Copper solid (Cu) Silver Nitrate solution (AgNO3) Hydrochloric Acid solution (HCl) Sodium Hydroxide solution (NaOH) Zinc solid (Zn) Hydrochloric Acid solution (HCl) Sodium Carbonate solution (Na2CO3) Calcium Chloride solution (CaCl2) 9 Physical and Chemical Changes Virtual Lab Name DATA ANALYSIS: 1. For each of the reactions in the Data Analysis, describe the indicator of chemical change that you noted in your Observations (~ 4 sentences per reaction). Use the table of Chemical Changes in the Introduction and Theory to pick your indication . Start your explanation with the indication of the chemical change (example, “In my observations, I noted [indicator from the table]”). Explain the change from your initial observations before mixing and after the reaction occurred. If you saw more than one indicator, pick the one that was the most notable. Chemicals Reacted Indication and Explanation of a Chemical Change Copper solid reacted with Silver Nitrate solution: Hydrochloric Acid solution reacted with Sodium Hydroxide solution Zinc solid reacted with Hydrochloric Acid solution Sodium Carbonate solution reacted with Calcium Chloride solution 2. Classify each of the events described below as either “chemical change” or “physical change”. Description of Event Classification An apple begins to rot. A wine glass falls to the floor and shatters. An ice cube melts. A silver spoon tarnishes. A wet towel becomes dry. 3. Give one example of a chemical change that you encounter in your everyday life. NOTE: You may NOT use any of the examples listed in question #2 above! 4. Give one example of a physical change that you encounter in your everyday life. NOTE: You may NOT use any of the examples listed in question #2 above! ChemicalChangesVirtualLab.docx Physical and Chemical Changes Virtual Lab INTRODUCTION AND THEORY: Matter and Its Physical and Chemical Changes Matter is defined as any material that has mass and occupies space. If we find that a sample of matter can be divided into more than one component using some means of physical separation, then we know our sample of matter must be a mixture. If we are unable to separate our sample of matter into different components, then it must contain only one type of material referred to as a pure substance. Thus, mixtures are made up of two or more pure substances. There are many different ways to physically separate a mixture. Each separation method is based upon some physical change. Examples of physical changes are: Physical Changes Change of: Examples: State (solid, liquid, gas) Boiling, Freezing Appearance Dissolving a solid in a liquid Shape Molding a lump of clay into a vase Size Breaking a piece of glass into pieces An example of a physical separation method is distillation, which separates pure substances based upon their differences in boiling point. Ethanol can be separated from a fermentation mixture (containing water, other organic chemicals, and non-volatile debris) using distillation. When you brew coffee, you are using gravity filtration to separate the soluble chemicals in the ground coffee beans from the insoluble grounds left in the filter paper. The means of separation here is the physical property of solubility in hot water. The key concept here is that physical separations, distillation, gravity filtration, etc., do not alter the chemical identity of any chemicals. The products after separation are the same chemicals that were initially used to make the mixture. This is very different from chemical changes (or “chemical reactions”) which result in formation of at least one new chemical substance. During a chemical change, some chemical bonds of the starting material(s) are broken, and some new chemical bonds are formed. At least one of the original chemicals must be used up (consumed), and at least one new chemical substance will be formed (produced). When two materials are added together, they may or may not undergo a chemical change. If a chemical change occurs, there often (but not always!) will be some sort of obvious evidence that a chemical reaction has taken place. Some examples of indications of a chemical change are: Chemical Changes Indication that a Chemical Change occurred: Permanent color change Formation of a solid (called a “precipitate” when it from the mixing of two solutions) Formation of a gas (continuous bubbling that isn’t caused by heating) Significant change in temperature (much hotter or colder) Emission of light or other form of electromagnetic radiation When you are asked to describe a material and its appearance before an experiment, you should include as much information as possible. You should describe its physical state (i.e., solid, liquid, or gas) and color. In addition, you might want to include the material’s opacity if it’s a solution/liquid (whether it is clear or cloudy), a description of its shape or texture if it’s a solid, a temperature estimate (is it warm or cool?), and whether it is uniform in appearance or has distinct regions. For example, if you were describing a chocolate chip cookie, you would observe that it was an approximately round-shaped solid with one flat side, composed of mostly tan-colored grainy material, and includes distinct smooth dark brown regions. If the cookie was fresh from the oven, you could note that it was warm to the touch, but cooling as it sat on the counter/cooling rack. Heterogeneous and Homogeneous Mixtures If no chemical reaction occurs when we combine two or more materials, then the result will be some sort of mixture. There are two different types of mixtures: homogeneous and heterogeneous. A homogeneous mixture is one in which the material is visually uniform in appearance throughout and has uniform chemical composition. An example would be if you dissolved some sugar in water, forming a uniform, clear and colorless solution of sugar water. Once the sugar has completely dissolved and dissipated, any sample of the mixture which you remove would have the same appearance; a clear, colorless solution. The mixture would also show the same chemical composition; the same proportions of sugar and water would be found in each sample you remove. Note that the process of dissolving the sugar in water does not break or form any new chemical bonds. We could physically separate this mixture by allowing the water to evaporate, and the sugar would be recovered intact as the non-volatile residue. In contrast, a heterogeneous mixture has distinct regions with (usually) different appearance and (always) different chemical composition. For instance, oil and vinegar salad dressing separates into two distinct layers – a layer containing the oil floating on top of the bottom layer containing the vinegar. If the oil and vinegar are similar in color, then the two layers may have similar “appearance”, but they clearly are chemically distinct! The Procedure used to conduct the chemical changes experiments was: A. Copper solid (Cu) and Silver Nitrate solution (AgNO3): 1. A piece of copper wire (Cu) and a test tube containing a small volume of silver nitrate solution (AgNO3) were obtained. 2. Before the reaction, the appearance of the copper wire (Cu) and the appearance of the silver nitrate solution (AgNO3) is observed and recorded, in detail on the data table— you will do this by watching the video linked in Falcon Online Content! 3. The copper wire (Cu) was dropped into the test tube containing the silver nitrate solution (AgNO3). 4. Record your observations of the reaction, in detail on the data table— you will do this by watching the video linked in Falcon Online Content! B. Hydrochloric Acid solution (HCl) and Sodium Hydroxide solution (NaOH): 1. A test tube containing a small volume of hydrochloric acid solution (HCl) and a test tube containing a small volume of sodium hydroxide solution (NaOH) were obtained. A digital thermometer was placed in the test tube of HCl solution. 2. Before the reaction, the appearance of the hydrochloric acid solution (HCl) and the appearance of the sodium hydroxide solution (NaOH) is observed and recorded, in detail on the data table— you will do this by watching the video linked in Falcon Online Content! 3. The sodium hydroxide solution (NaOH) was added to the test tube containing the hydrochloric acid solution (HCl) and the temperature was observed. 4. Record your observations of the reaction, in detail on the data table— you will do this by watching the video linked in Falcon Online Content! C. Zinc solid (Zn) and Hydrochloric Acid solution (HCl): 1. A test tube containing a small amount of zinc solid (Zn) and a test tube containing a small volume of hydrochloric acid solution (HCl) were obtained. 2. Before the reaction, the appearance of the zinc solid (Zn) and the appearance of the hydrochloric acid solution (HCl) is observed and recorded, in detail on the data table— you will do this by watching the video linked in Falcon Online Content! 3. The hydrochloric acid solution (HCl) was added to the test tube containing the zinc solid (Zn). 4. Record your observations of the reaction, in detail on the data table— you will do this by watching the video linked in Falcon Online Content! D. Sodium Carbonate solution (Na2CO3) and Calcium Chloride solution (CaCl2): 1. A test tube containing a small volume of sodium carbonate solution (Na2CO3) and a test tube containing a small volume of calcium chloride solution (CaCl2) were obtained. 2. Before the reaction, the appearance of the sodium carbonate solution (Na2CO3) and the appearance of the calcium chloride solution (CaCl2) is observed and recorded, in detail on the data table— you will do this by watching the video linked in Falcon Online Content! 3. The sodium carbonate solution (Na2CO3) was added slowly to the test tube containing the calcium chloride solution (CaCl2). 4. Record your observations of the reaction, in detail on the data table— you will do this by watching the video linked in Falcon Online Content!