V-25: You Light Up My Life Classifying Substances ChemCatalyst 1. If you were to drop a spoonful of salt, NaCl, into a glass of water, what would happen? 2. If you were to drop a gold ring into a glass of water, what would happen? 3. What do you think is different about the atoms of these two substances? Why do you suppose the gold atoms don t break apart? Fill out Lab Performance Sheet for today 10/13/09
V-25: You Light Up My Life Classifying Substances Work in groups of 3 to 4. 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.
V-25: You Light Up My Life Classifying Substances DEMO: Dissolving and conductivity can be demonstrated with a powdered sports drink and a light bulb assembly like the one shown below.
V-25: You Light Up My Life Classifying Substances 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.
V-25: You Light Up My Life Classifying Substances 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. Metal solids light up the bulb.
V-25: You Light Up My Life Classifying Substances Solubility and Conductivity Soluble: can be dissolved; Insoluble: cannot be dissolved
V-25: You Light Up My Life Classifying Substances Check-In Predict whether MgSO 4 (aq), commonly known as Epsom salts, will conduct electricity. State your reasoning.
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.
V-25: You Light Up My Life Review Add this diagram to your notes; fill in blanks, use V-25 lesson to help Soluble: can be dissolved; Insoluble: cannot be dissolved
V-26: Electron Glue Bonding Chem Catalyst A gold ring is made of individual gold atoms. 1. What keeps the atoms together so they just don t fall apart? 2. What parts of the atom do you think are responsible for keeping the atoms together in a solid?
V-26: Electron Glue Bonding How are atoms connected to one another? Chemical Bond: An attraction between atoms that holds them together in space.
V-26: Electron Glue Bonding Four Models of Bonding
V-26: Electron Glue Bonding Bonding also relates to the type of atom in the substance metal or nonmetal. Metal atoms Non-Metal atoms Metal & Non-Metal atoms Metallic Covalent Network Molecular Covalent Ionic
V-26: Electron Glue Bonding Four Models of Bonding Au gold SiO 2 sand H 2 O water NaCl salt Cu copper C 20 H 42 - paraffin C 12 H 22 O 11 sugar CaCl 2 calcium chloride Al aluminum C 2 H 6 O - ethanol CuSO 4 copper sulfate
V-26: Electron Glue Bonding Wrap-Up How are atoms connected to one another? Elements are substances in which only one type of atom is bonded together. Example: Na, Cu, Cl 2 Compounds are substances in which two or more types of atoms are bonded together. Example: NaCl, H 2 O, CuSO 4
V-26: Electron Glue Bonding Wrap-Up How are atoms connected to one another? A chemical bond is an attraction between atoms involving the valence electrons. There are 4 types of bonds: ionic, covalent network, molecular covalent, and metallic. Valence electrons are distributed in different ways between atoms depending on the type of bond.
Discussion Notes (cont.) The chart created in the previous lesson can now be labeled with the four types of bonds.
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.
V-26: Electron Glue Bonding Review (add to notes) Identify the type of bonding present in each group below: ionic bonding, molecular covalent, network covalent, or metallic bonding. 1. 2. 3. 4.
V-27: Electrons on the Move 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? Electroplating Metals Chem Catalyst Copper and chlorine atoms combine to form copper (II) chloride.
V-27: Electrons on the Move Electroplating Metals Lab Prep Can we get an element from a compound? Cu(s) CuSO 4 (aq) Electroplating: Using electricity to transform metal ions into neutral metal atoms
V-27: Electrons on the Move Electroplating Metals Lab Prep 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. Nickel Strips electrodes; allow electricity in and out of the solutiom Electroplating: Using electricity to transform metal ions into neutral metal atoms
V-27: Electrons on the Move Electroplating Metals Notes It is possible to transform metal cations in solution into neutral metal atoms, using electricity. Aqueous copper (II) sulfate, CuSO 4 (aq), is really copper cations, Cu 2+, and sulfate anions, SO 4 2. Before connecting to the battery
V-27: Electrons on the Move Electroplating Metals Notes 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
V-27: Electrons on the Move Electroplating Metals Notes 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.
V-27: Electrons on the Move Electroplating Metals Notes Properties: The properties of elements include color, hardness, and reactivity. Also solubility (whether it dissolves), and conductivity. CuSO 4 (aq) Cu(s)
V-27: Electrons on the Move Electroplating Metals Check-In 1. What is required to transform CuCl 2 (aq) into Cu(s)? 2. What is required to transform CuCl 2 (aq) into Au(s)?