Name: Hour: Teacher: ROZEMA / CHEMISTRY BONDING & CONDUCTIVITY

Name: Hour: Teacher: Ms. Rozema Starter Questions Grading: 2 pts = Date and full question written, question answered. 1 pt. = one requirement missing. 0 pts = no Q or A If you have an excused absence, write ABSENT and get the question from a classmate. Answer the question yourself. Date Copied Question & Best Attempt At Answer Points Paraphrase/Write the Question: 0 Answer: 1 2 Paraphrase/Write the Question: 0 Answer: 1 2 Paraphrase/Write the Question: 0 Answer: 1 2 Paraphrase/Write the Question: 0 Answer: 1 2

SUMMARY NOTES

You Light Up My Life Classifying Substances Purpose To collect evidence regarding some of the properties of substances and look for patterns in the results. Predict In the table below, predict whether each substance will dissolve in water, and whether it will conduct electricity. Test substances H2O (l), distilled water Al (s), aluminum foil C12H22O11 (s), sucrose (sugar) NaCl (s), sodium chloride SiO2 (s), silicon dioxide C20H42 (s), paraffin (wax) C2H6O (l), ethanol Cu (s), copper Predictions Conducts Dissolve? by itself? Conducts by itself? Test Results Dissolves? N/A N/A N/A Conducts when dissolved? CaCl2 (s), calcium chloride CuSO4 (s), copper sulfate Procedure Take the conductivity tester to each station. Test the pure substance for conductivity and record your result. Check to see if the substance dissolved in water. Finally, if the substance dissolved

Analysis 1. Which substances conduct electricity by themselves but do not dissolve in water? What type(s) of element(s) are these things made of? 2. Find all the things that dissolve in water but did not conduct electricity when dissolved (including water). Then, determine what kinds of elements they are made from. Substances that dissolved in water but do not conduct (FORMULAS) Types of elements the substances are made from (M, NM, M/NM) 3. What do the substances that do not conduct electricity once they are dissolved have in common? (Do not include water) 4. Find all the things that dissolve in water AND conduct electricity when dissolved. Then, determine what kinds of elements they are made from. Substances that dissolved in water and also conduct (FORMULAS) Types of elements the substances are made from (M, NM, M/NM) 5. What do the substances that conduct electricity when dissolved have in common? 6. Predict whether isopropanol, C3H8O (l) will conduct electricity. State your reasoning.

Dissolving Discussion: 1. Your teacher should have a container of salt and a beaker of water in the front of the class. Sketch a particle diagram, with whooshies, showing what the particles of salt look like in each salt crystal. Use darkened circles to show the atoms in salt, thinking about how they are packed and how they move. 2. Sketch a particle diagram, with whooshies, showing what the particles of water look like in the beaker. Use open circles to show the particles of water, thinking about how they are packed and how they move.

3. Now, let s say you take one of the salt crystals and place it in the beaker of water. a) After stirring it around, what happens to the salt crystal? b) Draw a particle diagram showing what you think is happening to the salt in the beaker of water. Use darkened circles to show the salt particles, and open circles to show the water particles. 4. Based on your experience and pictures, come up with a definition of dissolving based on the particle models. Be sure to say what the water is doing and what the salt is doing during the process of dissolving.

Bonding Models & Bonding Discussion: Model 1 Model 2 Model 3 Model 4 1. What are some things you notice about each of the models? What are some things you wonder about with each of the models?

The spheres in the models represent atoms, and the gray-shaded areas represent valence electrons. 2. What do you notice about the valence electrons in each of the models? Model 1: Model 2: Model 3: Model 4: 2. Two of these models dissolve in water. Which two do you think dissolved in water? Use the bonding models to explain why you think these dissolved in water. 3. Two did not dissolve in water. Use the bonding models to show why they did not.

4. The ability to conduct electricity involves the movement of electrons. Which model do you think has the ability to conduct electricity by itself? Why do you think this based on the picture of the bonding model? 5. Two of the substances in the previous lesson s lab were able to conduct electricity by themselves. What other evidence from the lab do you have to support that this model might hold true for these substances? 6. Based on the large group discussion, what model was decided upon that best fit the substances that conducted electricity? What were the BEST reasons the large group gave to support this?

7. One of the substances in the lab did not dissolve, nor did it conduct electricity. It is also considered an extremely hard solid. Which model best fits this substance based on the evidence from the lab? From the bonding model, why might this substance also be considered an extremely hard substance? 8. In the last unit, you learned about ionic substances such as sodium chloride, NaCl. a) From the lab, what properties do ionic substances possess? What evidence do you have from the lab that supports your statement? Give examples. b) From the last unit, what evidence do you have about the movement of electrons in an ionic substance? Think about what happens to Na and Cl when they form ions.

9. From your evidence, what bonding model(s) do NOT make sense for ionic bonding? Circle No for these models. Then give SPECIFIC REASONS, citing pieces of evidence from the lab or from the previous unit, that this model could not be a possible model for ionic bonding. Be sure to use the picture of the model and discuss how it relates to what properties you see in the lab or from the previous unit. 10. What bonding model(s) might possibly make sense for ionic bonding? Circle Maybe or Yes for this model. Then give SPECIFIC REASONS, citing pieces of evidence from the lab or from the previous unit that this model might make sense for ionic bonding. Be sure to use the picture of the model and discuss how it relates to the properties you see in the lab or previous unit.

Bonding Practice For Types of elements use the following letters: M = metal, NM = nonmetal, MD = metalloid, M/NM = metal and nonmetal combined, MD/NM = metalloid and nonmetal combined, M/MD = metal and metalloid combined Object Bonding Types of elements Nickel, Ni (s) Metallic Conduct electricity? (Y/N) Dissolve in water? (Y/N) Conducts when dissolved? (Y/N) Road Salt, MgCl 2 (s) Sand, SiO 2 (s) Sugar, glucose, C 6H 12O 6 (s) Ionic Network covalent Molecular Covalent 1. Isopropyl alcohol is used in rubbing alcohol. It has the formula C 3H 8O (l). (a) What types of elements is this substance made from? (b) Based on your answer from (a), what type of bonding do you think rubbing alcohol has? Be sure you use an object in the table as a comparison when you write. (c) Do you think this rubbing alcohol will dissolve in water? Why or why not?

2. You find a beaker labeled KCl (aq). (a) Is this substance a solid, liquid, or a gas? How do you know? (b) Based on the formula, what types of elements are found in this substance? What type of bonding does this substance have? Be sure you use an object in the table as a comparison when you write. (c) Do you think this substance will conduct electricity? Why or why not? (d) Do you think KCl (s) will conduct electricity? Why or why not? 3. Silicon carbide is a substance that is sometimes used in car brakes and bulletproof vests. It has the formula SiC (s). (a) What types of elements make up this substance? (b) Based on your answer from (a), what type of bonding do you think this substance has? Be sure you use an object in the table as a comparison when you write. (c) Do you think this substance will conduct electricity? Why or why not? (d) Do you this substance will dissolve in water? Why or why not?

4. Billon is an alloy made from copper and silver, CuAg (s). (a) Determine the type of bonding that is found in CuAg (s). (b) How did you determine the type of bonding that was found in CuAg (s)? Be as specific as possible in describing how you know. Be sure you use an object in the table as a comparison when you write. The pictures above show the two bonding models that are NOT covalent. 5 (a) Which picture would best describe the bonding found in the substance LiBr (s)?

(b) Using the picture of the bonding model, explain why LiBr (s) breaks apart into Li 1+ and Br 1- when it dissolves in water. In the picture, label which atoms are Li 1+ and which atoms are Br 1-. (c) Explain how you know which atoms are Li 1+ and which are Br 1-. Remember that the gray-shaded areas represent valence electrons. 6. (a) Which picture would best describe the bonding found in gold, Au (s)? (b) When electricity flows through wires, it is electrons that are moving. Use the picture of the bonding model to explain why gold conducts electricity so well. (c) Based on the picture of the bonding model, explain why gold does not dissolve in water.