Lab: Comparing Different Types of Solids Name ______
Purpose: To determine whether substances are ionic, network covalent, or molecular from some of their physical properties
Materials: Aluminum foil, distilled water, tongs, spot plate, hot plate, table salt, sand, stearic acid, sulfur, camphor
Procedure:
Testing for relative melting point
1. Use a small strip of aluminum foil, fold the foil to make separate areas for the five solids to be tested.
2. Place a small crystal of each solid on the foil.
3. Carefully place the foil on the hot plate. Turn on the hot plate – no higher than 5. Observe the order of melting. Record the order of melting.
4. Remove the foil with the tongs and dispose of the foil and contents in the wastebasket. Turn off the hot plate.
Testing for solubility
1. Use a spot plate. Add distilled water to 5 wells.
2. Add a small crystal of each solid to each well and stir with a toothpick. Record your observations. Note if the solubility is high, low, or none.
Testing for conductivity
1. Test the conductivity of each of the solutions prepared above. Record observations. Use a + if the solution conducts and – if it does not.
2. When finished, empty the spot plate into the waste jar and clean the spot plate.
Data: (Complete) ( 20 marks ) ( Communication )
Substance / Formula / Melting Point / Order of melting / Solubility in water / ConductivitySolid Liquid
Stearic Acid / C18H36O2 / 70 °C
Salt / NaCl / 801 °C
Sand / SiO2 / 1710 °C
Camphor / C10H16O / 175 °C
Sulfur / S / 94 °C
Conclusions : Knowledge ( 20 marks )
Substance / Type of Solid / Major Force / Reason for classificationStearic Acid
Salt
Sand
Camphor
Sulfur
Questions: (Inquiry)
1. Compare your order of melting to the melting points given in the table. (1)
______
______
______
2. Which physical property is best to identify ionic substances? Explain. (1)
______
______
3. Using a diagram, explain how one of these three unknown substances can conduct electricity in an aqueous solution. Would you expect this substance to conduct as a solid? Explain why or why not? (3)
4. Which physical property is best used to identify the molecular substances ( those made up of molecules)? Explain.(1)
______
______
Lab Discussion : Inquiry
1. For each type of compound, list the types of intermolecular forces that exist.(3)
a) polar molecule ______
b) nonpolar molecule ______
c) molecule with OH, NH, HF bonds ______
2. i) For each compound below, write down the types of intermolecular forces that exist between its molecules.
ii) Circle the substance that will have the higher boiling point. (13)
a) LiCl or HCl
______
b) Xe or I2 or Cu
______
c) CH3CH2OH or CH3CH2CH3
______
d) NO or N2
______
e) H2Se or H2Te
______
f) OF2 or CO2
______
g) NH3 or PH3
______
h) C2H6 or C4H10
______
i) CH3OH or CH3F
______
k) NH3 or PH3
______
l) CH3CH2OH or CH3CH2CH2OH
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m) CH3COOH or (CH3)2C=O
______
n) SiC or KCl
______
K /20 I /20 C / 20