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Section V: Building With Matter. Lesson 25 You Light Up My Life Lesson 26 Electron Glue Lesson 27 Electrons on the Move. Lesson 25: You Light Up My Life. Classifying Substances. ChemCatalyst. If you were to drop a spoonful of salt, NaCl, into a glass of water, what would happen?
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Section V: Building With Matter • Lesson 25 You Light Up My Life • Lesson 26 Electron Glue • Lesson 27 Electrons on the Move
Lesson 25: You Light Up My Life • Classifying Substances
ChemCatalyst • If you were to drop a spoonful of salt, NaCl, into a glass of water, what would happen? • If you were to drop a gold ring into a glass of water, what would happen? • What do you think is different about the atoms of these two substances? Why do you suppose the gold atoms don’t break apart?
Key Question • How can substances be sorted into general categories?
You will be able to: • classify substances into four categories based on solubility and conductivity • explain the difference between the terms soluble and insoluble • begin to describe the atomic makeup of substances based on whether they are soluble and/or conduct electricity
Prepare for the Lab • Work in pairs. • Wear safety goggles at all times during the lab. • Dissolve: To disperse evenly into another substance. For example, a solid can dissolve in a liquid. • Conductivity: A property that describes how well a substance transmits electricity.
Prepare for the Lab (cont.) • Dissolving and conductivity can be demonstrated with a powdered sports drink and a light bulb assembly like the one shown below.
Discussion Notes • Generalizations about substances that do not light up the bulb: • Compounds made up of C, H, and O atoms do not conduct electricity. • Compounds made up entirely of nonmetals do not light up the bulb. • Compounds made up of a combination of metals and nonmetals do not light up the bulb when they are in their solid form.
Discussion Notes (cont.) • Generalizations about substances that do light up the bulb: • Everything that lights up the bulb has a metal atom in it. • Compounds made of metal and nonmetal atoms, such as salts, light up the bulb when they are dissolved in water. (The sports drink is a solution of water, various salts, sugar, and a dye.) • Metal solids light up the bulb.
Discussion Notes (cont.) • Solubility and Conductivity
Discussion Notes (cont.) • We can place all the substances tested into one of the four categories. • Soluble: Describes a substance that is capable of being dissolved in another substance. • Insoluble: Describes a substance that is incapable of being dissolved in another substance.
Wrap Up • How can substances be sorted into general categories? • Not all substances dissolve in water. • Not all substances conduct electricity. • Solid metals and metal–nonmetal compounds dissolved in water conduct electricity.
Check-in • Predict whether MgSO4(aq), commonly known as Epsom salts, will conduct electricity. State your reasoning.
Lesson 26: Electron Glue • Bonding
ChemCatalyst • A gold ring is made up of individual gold atoms. • What keeps the atoms together? Why don’t they break apart from one another? • What parts of the atom do you think are responsible for keeping the atoms together in a solid?
Key Question • How are atoms connected to one another?
You will be able to: • define a chemical bond and describe the four basic types of chemical bonds • use chemical formulas to sort substances into bonding categories • predict the properties of a substance based on its chemical formula and bonding type
Prepare for the Activity • Work in pairs. • Chemical bond: An attraction between atoms that holds them together in space.
Prepare for the Activity (cont.) • Four Models of Bonding
Discussion Notes • The different locations of the electrons among atoms account for many different properties of substances.
Discussion Notes (cont.) • Ionic bonding: A type of chemical bonding that is the result of transfer of electrons from one atom to another. • Covalent bonding: A type of chemical bonding in which one or more pairs of valence electrons are shared between the atoms. Covalent bonding can be molecular covalent or network covalent.
Discussion Notes (cont.) • Metallic bond: A bond between metal atoms in which the valence electrons are free to move throughout the substance. • Molecule: A group of atoms covalently bonded together.
Discussion Notes (cont.) • The chart created in the previous lesson can now be labeled with the four types of bonds.
Discussion Notes (cont.) • Bonding also relates to the type of atom in the substance—metal or nonmetal. Nonmetal atoms Network Molecular covalent covalent Metal and nonmetal atoms Ionic Metal atoms Metallic
Wrap Up • How are atoms connected to one another? • A chemical bond is an attraction between atoms involving valence electrons. • There are four types of bonds: ionic, network covalent, molecular covalent, and metallic. • Valence electrons are distributed differently depending on the type of bond.
Check-in • Imagine that you have a mystery substance that does not dissolve in water and does conduct electricity. • What type of bonding will you probably find in your substance? Explain. • List one other property of your mystery substance.
Lesson 27: Electrons on the Move • Electroplating Metals
ChemCatalyst • 1. What is the charge on the copper ions in this copper chloride compound? 2. How do you think we could get solid copper from a sample of copper (II) sulfate, CuSO4? Copper and chlorine atoms combine to form copper (II) chloride.
Key Question • How can you extract an element from a compound?
You will be able to: • assemble an electroplating apparatus • explain how to extract elemental metal from an ionic compound through electroplating
Prepare for the Lab • Work in pairs. Wear safety goggles at all times. • The solution contains acid, which is corrosive. Before handling the nickel strip, rinse it with water.
Discussion Notes • It is possible to transform metal cations in solution into neutral metal atoms, using electricity.
Discussion Notes (cont.) • Aqueous copper (II) sulfate, CuSO4(aq), is really copper cations, Cu2+, and sulfate anions, SO42–. Before connecting to the battery
Discussion Notes (cont.) • Once the battery is hooked up, one nickel strip has a positive charge, and the other has a negative charge. After connecting to the battery
Discussion Notes (cont.) • Many elements are found in nature only in combination with other atoms in compounds. • While you cannot make gold by moving electrons, you can plate thin layers of gold onto jewelry.
Wrap Up • How can you extract an element from a compound? • Atoms are not destroyed when they combine to form compounds. Matter is conserved. • Ions are simply atoms or groups of atoms with charges on them because they either are missing electrons or have extra electrons. • Elements can be extracted from ionic compounds by moving electrons between atoms.
Check-in • What is required to transform CuCl2(aq) into Cu(s)? • What is required to transform CuCl2(aq) into Au(s)?