Virtual Solution Lab::

Transcription

1 Name A Solution is a type of homogeneous mixture formed when one substance dissolves in another. The particles of the mixing substances are evenly spread throughout. The substance that is dissolved is called the solute. The substance that does the dissolving is called the solvent. If a substance is soluble in water, it means the substance can dissolve in water. The amount of solute that will dissolve in 100 grams of water is called the solubility. Solubility is effected by temperature. The solubility of a substance is a characteristic property of the substance. When one substance is dissolved in another a physical change has taken place.

2 Virtual Solution Lab:: Look at the above animation. Explain how an ionic compound such as NaCl will dissolve in water. Look at the above animation. Explain why you do not see the salt particles after it is added to the water. Are the salt particles still present in the solution? Explain. Vocabulary: 1. Solubility 2. Saturation

3 3. Solute 4. Solvent Hypothesis: Now based on the above definitions and your common knowledge, make your hypothesis. Which (sugar, salt, or cornstarch) substance do you THINK will be more soluble in water? Why did you choose this substance? Lab Objective: To find the solubility of 3 solutes (sugar, salt, and cornstarch) in 3 different solvents (water, vegetable oil. rubbing alcohol).

4 Materials: Beakers Stirring Rods sugar salt cornstarch water vegetable oil rubbing alcohol Procedure: 1. Put 1 gram of each solute (sugar, salt, and cornstarch) in each of 3 beakers. 2. Add 100 ml of water to each beaker and stir. 3. Make observations in your data table. 4. Repeat using vegetable oil as the solvent. 5. Repeat using rubbing alcohol.

5 Data Table: Solute Solvent Sugar Water Salt Water Cornstarch Water Sugar Vegetable Oil Salt Vegetable Oil Cornstarch Vegetable Oil Sugar Rubbing Alcohol Salt Rubbing Alcohol Cornstarch Rubbing Alcohol Observation After Mixing Conclusion Questions: 1. Give a through explanation of your lab any observations or mistakes 2. Which solute had the greatest solubility according to your data?

6 3. Which solute has the least solubility according to your data? 4. Does this fit your hypothesis? Why or why not? 5. How does the amount of solute that you put into the solvent affect the solubility?

7 Make sure that students are familiar with the terms solubility, solute, and solvent. Also make sure they understand the factors such as temperature, surface area, pressure, molecule size, and stirring. Virtual Labs: Look at the 1 st virtual lab with your students and discuss what they see happening. Then on their paper or in their notebook, answer the question How does NaCl dissolve in water? Look at the 2 nd virtual lab with your students and discuss what is happening. Then on paper or in their notebook, answer the question Are the salt particles still in the water? Explain. Vocabulary: Allow students to do vocabulary using their textbook. I also make them write a sentence using the vocabulary in its correct context.

8 Hypothesis: Depending on the ability level of your students, you could do one or two things with the hypothesis: 1. Let them write their hypothesis on their own using the guiding questions given in the student handout. 2. Walk them through the hypothesis step by step. Conclusion Questions: These are answered based on the lab that each student conducts. I have my students turn their conclusion questions into a paragraph using the following format: R = Recall what you did during the lab E = Explain what you did? What were you trying to do? R = Reflect on the meaning (Did your results answer your predictions?) U = Uncertainty human errors, measurement errors, etc. Any error that could make a difference in your data. N = New questions or discoveries

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