There are really insightful discussions that can occur and misconceptions that can be addressed as students hear the responses of their peers. . Miscibility - Add 5 mL of distilled water into two test tubes. What evidence can show how the physical and chemical properties of the substances change? Classify the change a physical or chemical. Scrape a few crystals off the evaporating dish into a test tube.
Observe simple objects, patterns, and events and report their observations. Have students work in groups of 2 - 4. Some students get the idea that only chemical reactions can change the properties of a substance; however, it is important that students realize that physical reactions change the properties of substances as well. From your initial observations, you suspect that the two beakers contain the same compound. Use a test tube holder and heat each test tube gently and note any odor. Heterogeneous matter is not consistent in terms of properties.
Be sure not to lose any pieces. Record observations in Data Table 1. Next use the Ethyl Alcohol Ethanol squeeze bottle and rinse the bottom of the evaporating dish so that the drops of ethanol drip into the 600 mL beaker on the front desk. Have students look at their Reactant and Product Property Description page and let them note that these descriptions are also included there. Set Up: To close, as a class discuss whether each station is a chemical reaction, physical reaction, or both and share evidence that lead the students to that conclusion.
Shake the test tubes briefly to mix the contents. Weigh Boat B 5:37 pm 6:34 pm 10 min- melting where the pile of salt is faster than A. Predict whether or not the mass will change. In each of these observations, I noted if there were any changes in color, odor, if there were any gasses present, any sounds present, if the solution was soluble, or whether the substance changed from solid to liquid. Suck up these chemicals into their labeled pipets for later use. Do you see the white chunks forming? When students look for patterns in data to identify the signs of a chemical change based on their qualitative observations, they do just that! In the third column, determine whether you feel the reaction you observed was a chemical reaction, physical reaction, or both. I saw many chemical changes, but the most obvious and probably the best example is the mixing of acidic substances and basic substances, to change break the orginal bond in order to create a new one.
Have students turn to their unit plans and silently read the skill. Add a few drops of methyl alcohol to one test tube and amyl alcohol to the other. Each station has a sign with the procedure along with a description of the properties of the substances involved in the reaction. Touch a toothpick to the drop of water. What is a physical property? Use a second ring as a safety ring to protect the beaker from slipping off the ring stand Add 300 mL of water to the beaker, bring to a boil, and then shut off the burner.
Determine if the following scenarios represent a chemical or physical property. There is a sound that comes from the substance also. It's focus is scientific literacy. A chemical reaction takes place on the metals surface. Instructional Procedures Pre-lab discussion: Define matter, and physical and chemical changes.
After they get the routine, stations will move at 5 minutes per station. Examine each substance with a magnifying glass. And, what evidence can show how the physical and chemical properties of the substances change? This is a physical change because the molecule of water didn't change just its behavior did. The 5 signs of a chemical change are also included in the right column of the lab sheet. Assign each group a lab station to begin with. Set Up: The Reaction: Station 10: Bubblicious! Predict whether the mass will change after the reaction is completed.
State whether each substance is soluble or insoluble in water. Set Up: Station 11: Dissolving or Color Change? This unit focuses on chemical properties and chemical reactions. The second part depicts the effect of temperature on the reaction rate. Even if the student who shares their answer is correct, there are students in your class who are thinking the other way! It is important that students connect that the products in a chemical reaction will have new chemical and physical properties than the reactants. It is important that you include them all! Indications of chemical changes were preceded by the burning, rusting, fermenting, and decomposing of the substances. I created a table with observations from each experiment below. Describe, in general terms, some experiments in a laboratory that you could do to help prove or disprove that the beakers contain the same compound.