Lesson Plan Unit Plan: Chemical Bonding Topic: Hydrogen Bonding Grade and Content: 10th Grade Chemistry (Second Period 8:52 9:45) Do Now: Read the hydrogen bonding activity and be ready to explain the procedure. Aim: How can use surface tension to explain hydrogen bonding? Performance Objectives: Students will be able to (SWBAT): 1. Investigate hydrogen bonding and surface tension by seeing how many drops of a liquid they can place on a penny before it runs over. 2. Compare the physical properties of substances based upon chemical bonds and intermolecular forces Vocabulary: Hydrogen Bonding: special type of dipole dipole attraction which occurs when a hydrogen atom bonded to a strongly electronegative atom exists in the vicinity of another electronegative atom with a lone pair of electrons. Not a real bond Surface tension: The tension on the surface of water occurs when water molecules on the outside of the system align and are held together by hydrogen bonding to create an effect similar to a net made of atoms Intra molecular bonds: are those which occur within one single molecule Fro Previous Lesson: Molecular Polarity:A polar molecule results when a molecule contains polar bonds in an unsymmetrical arrangement. Material Lists: Cyclohexane Isopropanol Water Pennies Safety and Disposal: All materials are diluted and safe to handle. In the event a students gets contact with skin, the student need to rinse the area affected thoroughly with water for 10 15 minutes Anticipatory Opening: Video: What's the shape of a molecule?
Development of the lesson: What the teacher does What the student does 1 Put up DO NOW, AIM, and HW; setup materials. 2 Go over Do Now; ask students to explain the activity 3 Anticipatory Opening What does the molecular geometry of water tells us about polarity? The unequal distribution of the charges, makes asymmetrical and therefore polar molecule What is the main idea of the video? The shape of a molecule is arranged in away that it maximizes the attraction of opposite charges and minimize repulsion of unlike. Go over Vocabulary 4 Ask a student to read the Aim 5 Explain the activity to the students and assign groups. Ask each group to designate a person to get the materials. 6 Ask for volunteers to post their data on the board 7 Analysis of the data 8 Go over summative assessment activity 9 Answer the Aim. 10 Have a student to read the homework from the board. Students start Do Now. Students pay attention to the video Students write definitions and answer to the aim in their notebooks Students work on the activity One student from each group is chosen to write their results on the board Differentiated instruction: organizer worksheets, PowerPoint slides, Smart Notebook, questioning techniques, guided practice, independent work, team/pair/share whole class discussions, visuals, Internet sites, translations, color codes, student aided teacher demonstrations Summative Assessment Questions: 1. Compare the average number of drops placed on your penny for each liquid. What might account for any differences? The difference vary depend on the method for counting the drops or how many drops were added at once. 2. What steps did you include in your procedure to increase the reliability or reproducibility of your results? adding the drops all at the same height and same rate 3. Compare the average number of drops placed on your penny with the results obtained by some of the other lab groups. What might account for differences?
Mos of the results were very close. Differences might range from moving the tables to miscounting drops or misuse of the droppers 4. What were your predictions for the effect of each solute on the surface tension of the water? Answers may vary 5. What steps did you include in your procedure to increase the reliability or reproducibility of your results? Answers may vary 6. What are some practical applications of what you tested and learned? Answers may vary omework: e Learning Notes for revision: Standards: New York City High School Science Standards 1. The electronegative difference between two bonded atoms is used to assess the degree of polarity in the bond.(5.2k) 2. Molecular polarity can be determined by the shape of the molecule and distribution of charge. Symmetrical (nonpolar) molecules include CO2, H4, and diatomic elements. Asymmetrical (polar) molecules include HCl, NH3, and H2O. (5.2l) 3. Intermolecular forces created by the unequal distribution of charge result in varying degrees of attraction between molecules. Hydrogen bonding is an example of a strong intermolecular force. (5.2m) Common Core State Standards Connections Mathematical Practices: 5. Use appropriate tools strategically. 6. Attend to precision. 8. Look for and express regularity in repeated reasoning. CCR Reading Writing Speaking Listening Language 4. Comprehend as well as critique. 5. Value evidence.
Hydrogen Bonding Activity Hydrogen bonding in water is responsible for some of water s interesting properties. One of these properties is surface tension. Hydrogen bonding is due to the polarity of the oxygen-hydrogen, nitrogen-hydrogen, or fluorine-nitrogen bonds in molecules. Hydrogen bonding is an intra-molecular bond. That means it occurs between molecules, not within a molecule. Hydrogen bonding in water is responsible for some of water s interesting properties. In this activity, you will investigate hydrogen bonding and surface tension by seeing how many drops of a liquid you can place on a penny before it runs over. Using a dropper pipette, count the number of drops of each liquid you can place on the surface of a clean, dry penny. Organize your data clearly in this table: Liquid Trial # 1, drops Trial #2, drops Average # drops water cyclohexane alcohol Questions 1. Compare the average number of drops placed on your penny for each liquid. What might account for any differences? 2. What steps did you include in your procedure to increase the reliability or reproducibility of your results? 3. Compare the average number of drops placed on your penny with the results obtained by some of the other lab groups. What might account for differences? 4. What were your predictions for the effect of each solute on the surface tension of the water? 5. What steps did you include in your procedure to increase the reliability or reproducibility of your results? 6. What are some practical applications of what you tested and learned?
Properties of Water Lesson Plan Learning Objective: The purpose of this activity is to let the students experiment with water so that they may understand the concepts of Polarity Hydrogen Bonding Surface tension Scientific method Idaho State Science Standards Met: Kindergarten (Goals 1.2, 1.3, 1.6, 1.7, 1.8, 2.1), Grade 1 (Goals 1.2, 1.3, 1.6, 1.7, 1.8, 2.1), Grade 2 (Goals 1.2, 1.3, 1.6, 1.7, 1.8, 2.1) Grade 3 (Goals 1.2, 1.3, 1.6, 1.7, 1.8, 2.1), Grade 4 (Goals 1.2, 1.3, 1.6, 1.7, 1.8, 2.1), Grade 5 (Goals 1.2, 1.3, 1.6, 1.8, 2.1) Grade 6 (Goals 1.2, 1.3, 1.6, 1.8, 2.1), Grade 7 (Goals 1.2, 1.3, 1.6, 1.8, 2.1), Grades 8 9 (Goals 1.2, 1.3, 1.6, 1.8), Grade 10 (1.2, 1.3, 1.6) Materials: A penny, an eyedropper or pipette, a cup of water, and paper towels for each team of students. Background: Sometimes we call water H2O. That s because water molecules each have two hydrogen atoms and one oxygen atom. While water molecules are neutral as a whole, one end of the water molecule tends to have a positive charge while the other has a negative charge (polarity). Each end of a water molecule is attracted to the opposite charged end of another water molecule. This is called hydrogen bonding. Activity: How many drops of water can you fit on a penny? Make a prediction. Clean the penny using a paper towel. Don t use soap! Place the penny heads up on a flat surface. Fill the eyedropper and drop one drop of water on the penny at a time. After dropping five drops of water, take a look at your penny from the side view. What is happening? Continue to place drops of water on the penny. How many drops of water did your penny hold? What did the water on your penny look like? Were you surprised? Repeat the experiment and see if you can fit more drops of water on the penny. Follow up: After the activity, hold a discussion about the shape of the water on the penny and
why the so many water drops fit on the head of the penny. Introduce the term surface tension. When you put water drops on a penny, the drops pile up into a dome because of surface tension. Surface tension is produced by the force of attraction between water molecules. Within the liquid, each water molecule is attracted to its neighboring molecules, making them stick together. The water molecules at the top, however, stick only to the water molecules next to and below them. That s because there are none above them. This unbalanced attractive force causes the water to act as if it had a thin skin on the surface. As you add more drops, the force of gravity becomes stronger than the force of attraction among the water molecules at the surface. This causes the water to spill over the edge of the coin. Extension: Students will conduct a simple test to determine how many drops of each of three liquids can be placed on a penny before spilling over. The three liquids are water, rubbing alcohol, and vegetable oil. Students will make a hypotheses based on the previous experiment. Conduct the experiment using water, rubbing alcohol and vegetable oil and ask students to report their findings. Note: Oils have few, if any, hydrogen bonds amongst their large, organic molecules. When oil is dropped onto a flat, nonporous surface, it quickly spreads and forms a thin layer coating considerably more surface area than would a drop of water. Rubbing alcohol, on the other hand, is a mixture consisting of 70 percent isopropyl alcohol and 30 percent water. It does contain some hydrogen bonds within its structure, but not nearly as many as occur in pure water. Rubbing alcohol will form a bead when dropped onto a flat, nonporous surface, but the bead will be slightly flatter and larger in diameter than a corresponding bead of pure water.