oneCS-9A
Objective: To utilize the skills and processes of science in order to identify an unknown substance.
CSI Note: How can the unknown substance be identified?
Drill: 1. Get a Lesson Sheet from the
SET.2. Complete the Drill portion only
in your log book.
Identify the Unknown
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Identify as many characteristic properties as you can think of.
Density Boiling Point Freezing PointColor Solubility HardnessTaste Magnetism Conductivity
Think about what properties we can explore in class.
Identify the Unknown
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Look at the possible tests/measurements that can be
made on the unknown in a laboratory situation. Tell which tests you can/should explore.
Justify your selections.
Identify the Unknown
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Density
Yes
It is a characteristic property.
Identify the Unknown
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Taste
No
It is a characteristic property, but it is unsafe to taste unknown substances.
Identify the Unknown
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Color
Yes
It is a characteristic property.
Identify the Unknown
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Boiling Point
No
It is a characteristic property, but we do not
achieve the temperatures necessary to do this..
Identify the Unknown
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Shape
No
It is not a characteristic property.
Identify the Unknown
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Solubility
Yes
It is a characteristic property.
Identify the Unknown
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Magnetism
Yes
It is a characteristic property.
Identify the Unknown
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Mass
Yes
It is a not a characteristic property, but it is necessary
to calculate the density.
Identify the Unknown
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Volume
Yes
It is not a characteristic property, but it is necessary
to calculate the density.
Identify the Unknown
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Conduct the Investigation
Identify the Unknown
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Materials: Unknown substance Calculator
Graduated cylinder RulerPaper towels Paper cup
Triple beam balance WaterMagnet Spoon
Identify the Unknown
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Procedures:
Color
1. Observe the mystery substance. 2. Enter the color into the data chart.
Identify the Unknown
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Procedures: Density1. Zero the triple beam balance.2. Place the solid on the triple beam balance,
and determine its mass.3. Record the mass in the data chart. 4. Using a cup, add between 30mL and 60mL
of water to the graduated cylinder.5. Record the volume of water in the Volume
Side Chart as your starting volume.
Identify the Unknown
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Procedures: 6. Carefully slide the substance into the
graduated cylinder. 7. Record the total volume in the Volume
Side Chart.8. Calculate the volume of the substance by
subtracting the starting volume from the total volume.
9. Record the volume of the substance in the Volume Side Chart.
Identify the Unknown
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Procedures:
10. Calculate the density of the object by dividing the mass by the volume.
11. Record the density in the data chart.
Identify the Unknown
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Procedures:
Magnetism 1. Dry off the substance.2. Touch the magnet to the substance and observe the reaction.3. Record the reaction in the data chart.
Identify the Unknown
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Procedures:
Solubility
1. Fill a cup halfway with water.2. Carefully place the substance into the
water.3. Stir the substance with a spoon.4. Record the reaction in the data chart.
Identify the Unknown
oneCS-9A
ANALYSIS
Identify the Unknown
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Examine Chart 1, “Unknown Possibilities”. It provides a list of the suspects and the characteristic property that they leave behind. It also provides key characteristic properties for each substance.
Unknown Possibilities
Identify the Unknown
Suspect
Substance
Color Boiling Pt (oC)
SolubilityIn
Water
Density
(g/mL)
MagneticYes/No
Slick Nick
Nickel Silver 2914 NO 8.9 YES
Al Foil Aluminum
Silver 2467 NO 2.7 NO
Sylvia Shine
Silver Silver 2163 NO 10.5 NO
Cupric Carl
Copper reddish 2563 NO 8.96 NO
So Shady
Sodium Silver 883 YES 0.97 NO
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Compare the results from the examination of your mystery
substance with the substances in the chart. Check off the
characteristics that match your substance.
Identify the Unknown
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What substance do you think you discovered? Who do you think committed the crime? Why? (It is possible that you can’t yet identify the mystery substance, and that you no longer have any suspects.)
Identify the Unknown