Groups share hands-on activities, but a class rule is that every student must record data and answer questions in real time; in other words, students should not wait to copy data later. I also make sure that students know what group they are in, and where each group works in the lab. However, prior knowledge of this type is not necessary and this lesson can stand alone as the concepts presented are straightforward and the mini-labs reinforce the concepts nicely. I use this time to take care of administrative tasks such as taking attendance, and to check-in with students who may have been absent. I compliment team work, adherence to the procedures, and I stop class if there is a safety violation or common confusion about a procedure. A discrepant event occurs for many students when they discover that adding a certain volume of solute does not necessarily increase the volume of the solution by a corresponding amount. Knowledge about how the substances are made at the nanoscale make this an easier concept to comprehend, and that will come later in the course.
See how adding a known volume of salt contributes to the volume of water, and see how much salt you can add to 100 ml of water. The question of why adding 1 ml of solute not increase the solvent by 1 ml may not be immediately apparent to students. Answer Key Soluble Showing top 8 worksheets in the category - Answer Key Soluble. In the third lab, you will compare how quickly a crushed tablet dissolves compared to an uncrushed tablet. I explain that chemical composition is not obvious from simple observation. Some of the worksheets displayed are Work 7more solubility problems answer key, Use the provided solubility graph to answer the following, Solubility rules name chem work 15 1, Name sec date chem 1319 ws16 solubility work, Solubility curves work, Electrolytes work name key, Solubility rules work, Chapter 7 solutions work and key. You will record what happens in one-minute intervals, being careful not to jostle the cups.
. Many reactions happen in solutions. This lab-based lesson is designed to help students experience the fact that how and whether a solution can be made is determined in large part by the chemical composition of the solute and solvent. The Teacher's Guide in the reflection section of this lesson offers some additional comments and breaks down some of the choices I made when designing this lesson. Once you find your worksheet, click on pop-out icon or print icon to worksheet to print or download. Students learn about solubility through the practice of carrying out investigations. Worksheet will open in a new window.
How fast the solution can be made is determined in part by the temperature at which the mixture is created. I briefly discuss each of the mini-labs in the handout , but I do not go into too much detail. Solubility is an important topic in chemistry. Temperature, surface area, and possibly concentration were fairly easily observed. In the final lab, you will see how well different substances dissolve in water. During this time students conduct the various mini-labs.
What questions do you have about any of the labs? You will know it is dissolved when the bubbles are no longer being created. They record their work in Part 1 of the. At this point in the lesson I project my answer key to the second part of the Solubility Notecatcher, giving students the chance to volunteer and record answers. My students have some prior knowledge about different scales, as they have just completed a lesson on metric prefixes and scale. This warm-up activity should also give students time to think a little bit about solutions and the vocabulary used to describe them. After students have had a chance to so some reading and recording, I project the for students to compare their notes and ask questions.
Here is a that shows how students and I debrief each of the labs. Studying solubility also gives students another lens with which to peer into the nanoscale. This is an important part of the lesson--students use the vocabulary during the rest of the lesson. Note that I figured out how much 1 ml of salt was by looking at its density. I note that we do not observe these empty spaces at the macroscale because they are too small.
In the second lab, you will be doing a few things. The following materials are required to do these labs: Materials Mini-lab 1: 3 cups or 250 ml beakers 100 ml of hot water, room temperature water, and ice water food coloring 3 different colors Mini-lab 2: Mini-lab 2: 25 grams of sodium chloride NaCl A 100 ml graduated cylinder An electronic balance 50 ml of water Stirring rod Mini-lab 3: 1 Alka-Seltzer tablet 1 electronic balance Mortar and pestle Graduated cylinder 2 100 ml beakers Mini-lab 4: 15 grams of calcium carbonate 15 g of baking soda 15 g of magnesium sulfate mortar and pestle 100 ml graduated cylinder 250 ml beaker Students work alone by reading an excerpt from a text similar to with the goal of recording some key vocabulary and definitions related to solutions. If there is time I let students discuss this using a think-pair-share protocol, or if time is short I provide them with the answer by showing them a slide while explaining that at the nano scale there is a lot of empty space, and the salt can actually fill in some of this empty space. This copy of a student's was typical of what student's produced and it captured the important vocabulary I hoped they would get from this part of the lesson. All students will benefit from being able to think about substances at the different scales. They also see evidence of particle movement.
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