Introduction:
The ctions of the periodic table reflect the electron configurations of the elements and the sublevels occupied by the electrons. It is the electron configuration of the atom that determines its chemical reactivity. An element’s position in the periodic table is directly related to the size of the element’s atoms. The size of the atoms increas as you go down each column and decreas as you go from left to right. Elements who atoms have identical arrangements of electrons in their highest energy levels have similar properties and make up a family of elements in the periodic table (vertical columns). Elements on the Periodic Table are grouped into metals, nonmetals and metalloids bad on some key physical and chemical properties.
Elements combine chemically to form compounds. Bulk properties (physical and chemical) are determined by microscopic structures and interactions between atoms, ions and molecules. Common houhold substances span the whole range of materials from ionic compounds to molecular compounds, and to elements.
Purpo:
Students will investigate and determine the physical and chemical properties of lected elements and common houhold chemicals to further students’ understanding of relationships between microscopic structures/interactions and bulk properties.
Materials / Equipment:
Aluminum
Carbon
Silicon
Sulfur
Magnesium
Zinc
Copper
祛湿粥的配方Nail
Hammer or other hard, solid
24 cell well plate
Forceps
Conductivity tester
1.0 M HCl, 5 mL
0.1 M CuCl
2, 5 mL
Epsom salt
Alum powder
Table sugar powder
Rock candy
Copper metal
24 cell well plate
Well-plate grid paper
Forceps
Spatula
Mortar and pestle
Conductivity tester
Kimwipes
Distilled water
400-mL beaker as waste jar
Safety:
∙Always wear safety glass and apron in the chemistry lab.
∙Never eat or drink in the chemistry lab.
∙Hydrochloric acid solution is corrosive to eyes and skin.
∙Cupric chloride solution is toxic if ingested.
勇敢的什么∙Avoid contact of all chemicals with eyes and all body tissues.
Pre-lab questions:
∙Part A – Properties of Selected Elements
1.What is an element?
2.What are the general features of the Periodic Table of Elements?
3.What is a metal?
4.What is a nonmetal?
5.What is a metalloid?
6.What are required for any material to conduct electricity?
7.What is brittleness?
8.What is malleability?
∙Part B – Properties of Common Houhold Substances
9.What is Epsom salt? What is the chemical formula for Epsom salt?
10.What is Epsom salt ud for?
11.What is table sugar? What is the chemical formula for table sugar?问候语英语
12.What is rock candy? How is rock candy made?
13.What is alum? What is alum generally ud for?
Procedure:
Part A – Properties of Selected Elements
1.Using a periodic table, determine the chemical symbol for each of the ven
elements to be tested. Fill in the chemical symbol for each element on the data
table.
2.Place a piece of white notebook paper on the lab table. Using a pencil or pen to
draw lines, divide the paper into eight squares (four squares across, two down.).
Label each square with the chemical symbol of one of the ven elements to be来小鹏
tested.
3.Obtain a well plate and well plate data sheet. (If you place the well plate on top
of the data sheet, you will e that they “fit”) You will be testing each element in
cupric chloride solution AND hydrochloric acid solution in the well plates. On
the well plate data sheet, label two squares with each chemical symbol of the
elements to be tested. There are a total of 7 elements, so you will have 14 squares
labeled.
4.Take the well plate and well plate data sheet to the chemical table and place a
small piece of the appropriate element in each labeled well. (NOTE: Do not
touch any of the elements with your hands. U forceps to obtain each sample.)
5.At your lab station, remove one sample of each element and place it on the sheet
of notebook paper in the properly labeled square.
∙Physical Properties
1.Obrve and record the color of each element in the Data Table. Is the sample
silver, gray, colored, etc…? Be very specific in recording obrvations.
2.Obrve and record the luster of each element in the Data Table. Is the
sample lustrous and shiny, slightly shiny, dull?
3.Record any other physical properties that are obrved about each element in
the Data Table. Be specific in your obrvations. What form is the sample in?
Is the sample crystalline, flaky, rough, smooth, flat and plate-like, rocky, in
strips? Is there any odor or are any vapors given off? (Note: Avoid breathing any vapors directly. Instead of smelling a sample directly, waft the vapors
from the sample toward your no.)
4.Determine whether each element is malleable or brittle. To do this, position a
nail on the sample and gently tap the nail with a hard, solid object (hammer,
piece of wood, small book) A material is malleable if it flattens or bends
饭包的做法without shattering. A sample is brittle if it shatters or cracks into pieces when struck. Record your results in the Data Table.
5.U the conductivity apparatus to test the conductivity of each sample. Touch
both electrodes to the element being tested. Make sure the electrodes are not
touching each other. Pay clo attention to the relative intensity of the light.
Record accordingly.
∙Chemical Properties
6.Place the well plate on top of the well plate data table. U the forceps to replace
the chemical element samples you examined into their proper places in the well plate.
7.Obtain one pipet full of HCl Determine the reactivity with acid of each sample by
adding 10 drops of 1 M HCl to one well of each sample—a total of 7 wells will have the acid in them. The other 7 wells will be empty at this point.
8.Evidence for a chemical reaction may be the formation of gas bubble and/or
discoloration on the surface of the element. Some reactions may be slow to
start—be patient. Obrve and record results in the Data Table.
. Determine the reactivity with cupric chloride
9.Obtain one pipet full of CuCl
2
solution of each sample by adding 10 drops of CuCl
to the remaining wells.
2
花椒泡脚的功效Obrve and record the results in the Data Table.
10.After allowing the samples to react (about 5 minutes) carefully decant the HCl off
the samples with the pipet and transfer to the small waste beaker at your station.
Decant the CuCl
into another waste beaker. Empty the solid samples into the
2
trash, but do NOT try to rin the well plates! This is tricky to do without
splattering water everywhere—just let your teacher do it!
Part B – Properties of Common Houhold Substances
∙Physical Properties of Bulk Samples
1.There are four bulk samples: Epsom salt, alum, rock candy and metallic copper.t60内存
2.Obrve and record the color of each substance in the Data Table. Is the sample
silver, gray, colored, etc…? Be specific in recording obrvations.
3.Obrve and record the luster of each element in the Data Table. Is the sample
lustrous and shiny, slightly shiny, dull?
4.Record any other physical properties that are obrved about each element in the
Data Table. Be specific in your obrvations. What form is the sample in? Is the sample crystalline, flaky, rough, smooth, flat and plate-like, rocky, in strips? Is there any odor or are any vapors given off? (Note: Avoid breathing any vapors
directly. Instead of smelling a sample directly, waft the vapors from the sample
toward your no.)
5.U the conductivity apparatus to test the conductivity of each bulk sample.
Touch both electrodes to the element being tested. Make sure the electrodes are
not touching each other. Pay clo attention to the relative intensity of the
羊肉包
indicator light. Record accordingly.
∙Physical Properties of Powdered Samples
6.Determine whether each substance is malleable or brittle. There are veral ways
to accomplish the task: (a) Place small amount of test substance between two
sheets of clean paper. U tip of large stainless steel spatula to apply pressure on
the samples. (b) Place small amount of test substance into a mortar. Grid the
powdery sample. Either method would be fine. A material is malleable if it
flattens or bends without shattering. A sample is brittle if it shatters or cracks into pieces when struck. Carefully record your results in the Data Table.
∙Solubility in Water and Conductivity of the Resulting Solution
7.On the well plate, establish proper identification of each pure substance.
8.Fill 5 wells with distilled water to 2/3 of each well.
9.Test conductivity of each well. Obrve and record results in the Data Table.
10.Take small amount of each sample and put into wells 2-5. Well #1 is kept as the
control for this part of the experiment. Prior to further analysis for each substance, the control sample has to be tested. Obrve and record solubility results in the
Data Table.
11.Test conductivity for each solution. Note: cross contamination possibility has to
be minimized. Thoroughly clean the tips of the battery tester prior to the next
measurement. Pay clo attention to the intensity of the indicator light.
12.In the 6th well, fill it with tap water. Test conductivity and record findings.
13.Repeat steps 7-11 one more time.
Post-lab questions:
∙Part A – Properties of Selected Elements
1.Review the data gathered for the ven elements. Sort the ven elements into
groups, bad on similarities and differences in their physical and chemical
properties. Using this information plus information from your book, classify each group as metal, nonmetal, or metalloid.
2.Are there any inconsistencies within the groups you made? Do any elements
em to have properties of both groups? Which? Explain.
3.Look at the location on the periodic table of each of the eight elements tested in
this lab. How do the properties of the elements compare to their general
position on the periodic table? Make generalizations about the position of the
metals, nonmetals, and metalloids on the periodic table.
4.Predict the physical and chemical properties of the following elements which
were not tested in this lab—lenium, calcium, and cobalt.
∙Part B – Properties of Common Houhold Substances
5.Are there any differences of physical properties among the 4 houhold chemicals?
6.Obtain melting points for all four test chemicals via internet. Is there any trend?
7.Can the four pure substances be parated into three groups? Explain if your
answer is yes.
Extension Questions/Activities:
1.An aqueous sample does not conduct electricity when the conductivity tester is
ud. Does it mean the aqueous sample is pure water? Explain. (Part A)
2.Given the following melting point data, are there any generalizations you can
make about the melting points of metals versus nonmetals? Are there any
exceptions? Explain.
Aluminum 6600 C
Carbon 36520 C
Copper 10630 C
Magnesium 6490 C
Silicon 14100 C
Sulfur 1130 C
Zinc 4200C
