Chemistry+Activities+ACS

Heat is often evidence of a chemical change. Post this question on the board: “How do we know if matter has undergone a chemical change?” Materials: Per class: dollar bill, tongs, matches, salt, alcohol, water Per student: index card, copy of Digestive System Parts chart (Appendix A-1) Procedure: 1. Instructional Focus Activity: you will need a dollar bill or higher denomination, tongs, matches or a lighter, salt, a solution of 50% alcohol and 50% water (you can mix 95% alcohol with water in a 1:1 ratio, if desired). Before the students enter, complete the following steps: • Prepare the alcohol and water solution. You can mix 50 ml of water with 45 ml of 91% alcohol. • Add a pinch salt or other colorant to the alcohol/water solution, to help produce a visible flame. • Soak a dollar bill in the alcohol/water solution so that it is thoroughly wet. • Use tongs to pick up the bill. Allow any excess liquid to drain. Move the damp bill away from the alcohol-water solution.
 * Burning Money Activity: **

When students arrive, tell them that you are going to light this one dollar bill on fire. Ask: “What changes would you expect to see and why?”

Light the bill on fire and allow it to burn until the flame goes out. Have students discuss possible explanations in small groups.

Scientific Concept Behind Burning Money: A combustion reaction occurs between alcohol and oxygen, producing heat and light (energy) and carbon dioxide and water. C2H5OH + 4 O2 -> 2 CO2 + 3 H2O + energy When the bill is soaked an alcohol-water solution, the alcohol has a high vapor pressure and is mainly on the outside of the material (a bill is more like fabric than paper, which is nice, if you've ever accidentally washed one). When the bill is lit, the alcohol is what actually burns. The temperature at which the alcohol burns is not high enough to evaporate the water, which has a high specific heat, so the bill remains wet and isn't able to catch fire on its own. After the alcohol has burned, the flame goes out, leaving a slightly damp dollar bill. http://chemistry.about.com/od/demonstrationsexperiments/ss/burnmoney_2.htm

Students are introduced to the idea that matter is composed of atoms and molecules that are attracted to each other and in constant motion. Students explore the attractions and motion of atoms and molecules as they experiment with and observe the heating and cooling of a solid, liquid, and gas. Students help design experiments to test whether the temperature of water affects the rate of evaporation and whether the temperature of water vapor affects the rate of condensation. Students also look in more detail at the water molecule to help explain the state changes of water. Students experiment with objects that have the same volume but different mass and other objects that have the same mass but different volume to develop a meaning of density. Students also experiment with density in the context of sinking and floating and look at substances on the molecular level to discover why one substance is more or less dense than another. Students look more deeply into the structure of the atom and play a game to better understand the relationship between protons, neutrons, electrons, and energy levels in atoms and their location in the periodic table. Students will also explore covalent and ionic bonding. Students investigate the polarity of the water molecule and design tests to compare water to less polar liquids for evaporation rate, surface tension, and ability to dissolve certain substances. Students also discover that dissolving applies to solids, liquids, and gases. Students explore the concept that chemical reactions involve the breaking of certain bonds between atoms in the reactants, and the rearrangement and rebonding of these atoms to make the products. Students also design tests to investigate how the amount of products and the rate of the reaction can be changed. Students will also explore endothermic and exothermic reactions.
 * http://www.middleschoolchemistry.com/lessonplans/ **
 * [|Chapter 1: Matter—Solids, Liquids, and Gases] **
 * 1) 1. [|Molecules Matter]
 * 2) 2. [|Molecules in Motion]
 * 3) 3. [|The Ups and Downs of Thermometers]
 * 4) 4. [|Moving Molecules in a Solid]
 * 5) 5. [|Air, It's Really There]
 * [|Chapter 2: Changes of State] **
 * 1) 1. [|Heat, Temperature, and Conduction]
 * 2) 2. [|Changing State—Evaporation]
 * 3) 3. [|Changing State—Condensation]
 * 4) 4. [|Changing State—Freezing]
 * 5) 5. [|Changing State—Melting]
 * [|Chapter 3: Density] **
 * 1) 1. [|What is Density?]
 * 2) 2. [|Finding Volume—The Water Displacement Method]
 * 3) 3. [|Density of Water]
 * 4) 4. [|Density—Sink and Float for Solids]
 * 5) 5. [|Density—Sink and Float for Liquids]
 * 6) 6. [|Temperature and Density]
 * [|Chapter 4: The Periodic Table & Bonding] **
 * 1) 1. [|Protons, Neutrons, and Electrons]
 * 2) 2. [|The Periodic Table]
 * 3) 3. [|The Periodic Table & Energy Level Models]
 * 4) 4. [|Energy Levels, Electrons, and Covalent Bonding]
 * 5) 5. [|Energy Levels, Electrons, and Ionic Bonding]
 * 6) 6. [|Represent Bonding with Lewis Dot Diagrams]
 * [|Chapter 5: The Water Molecule and Dissolving] **
 * 1) 1. [|Water is a Polar Molecule]
 * 2) 2. [|Surface Tension]
 * 3) 3. [|Why Does Water Dissolve Salt?]
 * 4) 4. [|Why Does Water Dissolve Sugar?]
 * 5) 5. [|Using Dissolving to Identify an Unknown]
 * 6) 6. [|Does Temperature Affect Dissolving?]
 * 7) 7. [|Can Liquids Dissolve in Water?]
 * 8) 8. [|Can Gases Dissolve in Water?]
 * 9) 9. [|Temperature Changes in Dissolving]
 * [|Chapter 6: Chemical Change] **
 * 1) 1. [|What is a Chemical Reaction?]
 * 2) 2. [|Controlling the Amount of Products in a Chemical Reaction]
 * 3) 3. [|Forming a Precipitate]
 * 4) 4. [|Temperature and Rate of a Chemical Reaction]
 * 5) 5. [|A Catalyst and the Rate of Reaction]
 * 6) 6. [|Using Chemical Change to Identify an Unknown]
 * 7) 7. [|Energy Changes in Chemical Reactions]
 * 8) 8. [|pH and Color Change]
 * 9) 9. [|Neutralizing Acids and Bases]
 * 10) 10. [|Carbon Dioxide Can Make a Solution Acidic]

[] Students will experience all five elements of inquiry as they ask questions about M&M’s in water, design and conduct experiments to answer these questions, and develop explanations based on their observations. In this chapter, students compare the properties of four different household crystals to the properties of an unknown crystal. Even though different liquids may look similar, they act differently when placed on various surfaces. Students compare the way four known liquids and an unknown liquid bead up, spread out, or absorb into different surfaces. In this chapter, students participate in activities that help them better understand the different factors that affect the solubility of solids, liquids, and gases. In this chapter, students gain experience with the evidence of chemical change—production of a gas, change in temperature, color change, and formation of a precipitate. In the first activity from this chapter, students consider how heating and cooling affect molecular motion. The subsequent activities extend this idea to explore the relationship between temperature and the state changes of water. In this chapter, students will explore the concept of density through the familiar experiences of sinking and floating.
 * 1) 1. [|Mysterious M&Ms]
 * 2) 2. [|Racing M&M Colors]
 * 3) 3. [|Colors Collide or Combine?]
 * 4) 4. [|Investigating the Line]
 * 5) 5. [|M&M's in Different Temperatures]
 * 6) 6. [|M&M's in Different Sugar Solutions]
 * 1) 1. [|Curious Crystals]
 * 2) 2. [|Crushing Test]
 * 3) 3. [|Solubility Test]
 * 4) 4. [|Recrystallization Test]
 * 1) 1. [|Look-alike Liquids]
 * 2) 2. [|Developing Tests to Distinguish Between Similar-Looking Liquids]
 * 3) 3. [|Using Color to See How Liquids Combine]
 * 4) 4. [|Using the Combining Test to Identify Unknown Liquids]
 * 1) 1. [|Defining Dissolving]
 * 2) 2. [|Dissolving a Substance in Different Liquids]
 * 3) 3. [|Temperature Affects Dissolving]
 * 4) 4. [|Dissolving Different Liquids in Water]
 * 5) 5. [|Temperature Affects the Solubility of Gases]
 * 6) 6. [|A Dissolving Challenge]
 * 1) 1. [|Powder Particulars]
 * 2) 2. [|Using Chemical Change to Identify an Unknown]
 * 3) 3. [|Exploring Baking Powder]
 * 4) 4. [|Change in Temperature—Endothermic Reaction]
 * 5) 5. [|Production of a Gas—Controlling a Chemical Reaction]
 * 6) 6. [|Change in Temperature—Exothermic Reaction]
 * 7) 7. [|Color Changes with Acids and Bases]
 * 8) 8. [|Neutralizing Acids and Bases]
 * 9) 9. [|Comparing the Amount of Acid in Different Solutions]
 * 10) 10. [|Formation of a Precipitate]
 * 1) 1. [|Matter on the Move]
 * 2) 2. [|Evaporation]
 * 3) 3. [|Condensation]
 * 4) 4. [|Exploring Moisture on the Outside of a Cold Cup]
 * 5) 5. [|Exploring Moisture on the Outside of a Cold Cup (for dry evironments)]
 * 6) 6. [|From Gas to Liquid to Solid]
 * 1) 1. [|Defining Density]
 * 2) 2. [|Comparing the Density of an Object to the Density of Water]
 * 3) 3. [|Comparing the Density of Different Liquids]
 * 4) 4. [|Changing the density of a liquid—Adding salt]
 * 5) 5. [|Changing the density of a liquid—Heating and cooling]
 * 6) 6. [|Changing the density of an object—Adding material]
 * 7) 7. [|Changing the density of an object—Changing shape]