Physical Properties of Elements and Compounds

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					Lab 3: Physical Properties of Elements and Compounds This experiment will involve the observation of physical properties of some elements and compounds. Record all observations in the table provided. When using the conductivity tester, wipe it off after testing a powder or liquid. DO NOT HANDLE THE SAMPLES IN THE PLASTIC CONTAINERS. As you record these observations, think about the following differences: 1. metals vs. nonmetal 2. element in elementary form vs. element in the form of a compound 3. covalent (molecular) compounds vs. ionic compounds PROCEDURE: Record all observations in the Data Tables provided. In describing appearance, make sure you note physical state, color and texture. A) Appearance and properties of metals. 1. Examine the aluminum, copper, zinc and lead. Describe their appearance and test their electrical conductivity. See if you can find any differences between the metals. 2. Are these metals soluble in water? B) Appearance and properties of metalloids. 1. Describe the appearance of the metalloids, silicon and antimony. 2. Test their electrical conductivity. C) Appearance and properties of nonmetals. 1. Describe the appearance of the sulfur. Test its electrical conductivity. 2. There are 3 forms, or allotropes, of carbon: diamond, graphite and charcoal. Describe the appearance of each. Test the graphite and charcoal for electrical conductivity. 3. Describe the appearance of iodine. DO NOT OPEN THE CONTAINER. 4. Describe the appearance of nitrogen and oxygen at room temperature. What are their physical states? D) Appearance and properties of ionic compounds. 1. Describe the appearance of some compounds of the metals you have examined: CuSO4, CuCl2, Zn(NO3)2, Al2(SO4)3, FeCl3, Fe(NO3)3. 2. Test the electrical conductivity of solid Fe(NO3)3. 3. Test the water solubility of the Fe(NO3)3 by adding a few crystals of the solid to 10-20 ml of water in a 50 or 100 ml beaker. Stir to see if they dissolve. (A previous group may have done this already. In that case, examine the solution.) Test the electrical conductivity of the mixture of Fe(NO3)3 and water. 4. In a previous experiment, you added CuCl2 to water. Did it dissolve? Did the solution conduct electricity? Add these observations to your data table. E) Appearance and properties of covalent (molecular) compounds. 1. From your recollections, describe the appearance of a common covalent compound, CO2. 2. Describe the appearance of some other common covalent compounds: H2O, C12H22O11 (sucrose, or table sugar), C3H8O3 (glycerol, or glycerine), C22H46 (parafin, or wax). 3. Test the electrical conductivity of the water, glycerol, and sugar. 4. Test the water solubility of a small amount of the sugar. Test the electrical conductivity of the solution. (A previous group may have already mixed some sugar and water. In that case, examine the solution.) 5. Do you think wax dissolves in water? Add this to your data table. Be sure to wash your hands at the end of this experiment!

DATA TABLES You have been given the data tables for this lab. By breaking up what could have been one huge table into several categorical tables you should be able to identify trends readily. This will also help when you reference specific data as part of your discussion of lab results.
Name Element or Compound? (Symbol) Type of element or compound (metal, nonmetal or metalloid?) (ionic or covalent compound?) Metal Covalent Physical State Color Texture Properties

Iron water

Element (Fe) Compound (H2O)

solid liquid

gray color-less

smooth, shiny clear

conducts electricity, not water soluble does not conduct

INFORMAL LAB REQUIREMENT Fill in the table to indicate whether each substance tested is an element or compound. For each compound, indicate whether it is ionic or covalent. For each element, classify it as metal, nonmetal or metalloid. Fill in all data requested in the procedures. NOTE: Not all samples are tested for each property! Follow directions! Photocopy the table and include the copy in your informal lab report. Remember to tape the original table in your laboratory notebook. TYPED INTRODUCTION In your own words (avoid 1st person), introduce the lab and summarize the scientific theory/principles that form the basis for this experiment. Organize your ideas in paragraph form with topic sentences. Usually 2-3 paragraphs is sufficient. Technical writing does demand being precise and concise. An introduction might include the basic methodology you will use in the lab, but NEVER outlines the steps to be followed or provides the type of detail that belongs in the procedure. Likewise, an introduction NEVER discusses results from the actual laboratory. Instead, an introduction describes fully the purpose of the lab and states the hypothesis, where applicable. In this lab, it is appropriate to define what each category of element is (metal, metalloid, nonmetal, ionic compound, covalent compound) and include any fore-knowledge you have on the topic. Show you understand the chemical principles or concepts relevant to this experiment. The Introduction summarizes what is known BEFORE the experiment. You may find that checking another source is necessary and helpful to better understand and introduce the principles involved. ALWAYS cite any outside sources you use to develop your introduction. It is not necessary to cite your text when you are simply fact checking. Do not borrow phrases or excerpt from the text; put ideas into your own words. QUESTIONS 1. Fill in the table to indicate whether each substance is an element or compound. For each compound, indicate whether it is ionic or covalent. For each element, classify it as metal, nonmetal or metalloid. 2. For each of the five types of elements and compounds examined, list at least two physical properties observed in this experiment. For each physical property, explain how it is shared within the group or varies within the group. (Be sure to answer all ten parts of this question.) 3. Indicate at least one physical property that is different between: a) metals and most nonmetals, b) metals and metalloids and c) ionic compounds and covalent compounds. 4. For one compound, compare the physical properties of the compound to the properties of the elements that make up that compound.

Table 1: Metal Elements
Name Element or Compound? (Symbol) Type of element or compound Physical State Color Texture Properties

aluminum copper zinc lead

Table 2: Metalloid Elements
Name Element or Compound? (Symbol) Type of element or compound Physical State Color Texture Properties

silicon antimony

Table 3: Nonmetal Elements
Name Element or Compound ? (Symbol) Type of element or compound Physical State Color Texture Properties

sulfur carbon (diamond) carbon (graphite) carbon (charcoal) iodine nitrogen oxygen I2

Table 4: Ionic Compounds
Name Element or Compound? (Symbol) Type of element or compound Physical State Color Texture Properties

Copper(II) sulfate Copper(II)chloride Zinc nitrate Aluminum sulfate Iron(III) chloride Iron(III) nitrate

CuSO4 CuCl2 Zn(NO3)2 Al2(SO4)3 FeCl3 Fe(NO3)3 X X X X X

Iron(III) nitrate solution Table 5: Covalent Compounds
Name

Element or Compound? (Symbol)

Type of element or compound

Physical State

Color

Texture

Properties

Carbon dioxide Water Sucrose Sucrose solution Glycerol Paraffin C12H22O11 X C3H8O3 C22H46 X X X X