Explore 104 Particular Properties
You should be able to:
Name_____________________ Date_______ Period ________
- Conduct a scientific investigation to determine properties of each compound
- Properly follow protocols for testing the hardness, conductivity, solubility and melting point
- Correctly use electrical conductivity meter
- Use evidence from the testing along with logic to sort the compounds into groups with similar
properties
Particular Properties pages 104 - 109
1. Look at figure 3.3 on page 105: Will soapy water dissolve the blob of tar on this car? Why or why not?
Your Main Job is to Figure out what Type of Molecule each compound is and the
Characteristic Properties of each Type of Molecule.
Appearance and Relative Hardness


describe how each compound looks
results = white & granular (like sand), powder, tablet, flaky
Relative Hardness


use a spatula to press against each compound
results = soft or hard/brittle
Testing Electrical Conductivity



touch each sample with both probes of the conductivity meter
make sure the probes do not touch each other
results = yes (weak or strong) or no
Determining Relative Solubility
 fill each well 3/4 full with distilled water mixing with your scupula
 results = yes or no
Determining Relative Melting Points


place 1 g of compound in a test tube
heat for 3 minutes in hot water bath
o if it melts your are done if NOT follow the next step
 heat for 3 minutes in a direct flame (Bunsen burner)
 results = low (easy to melt), medium (harder to melt), high (really hard to melt),
2. Fill in the data table below with your results. Perform the test in order from #1 to #7
Properties
Substances
Appearance
(white/powder/
crystal/greasy)
Aspirin
Cornstarch
Deicer
(CaCl2)
Epson
salts
Paraffin
wax
Sugar
Table Salt
(NaCl)
Vitamin C
Hardness
Conductivity
of Solid (yes/no)
Soluble
in
water?
Conductivity in
water
Melting
Point
(weak/strong/NO)
Medium
Low
High
High
Low
Medium
High
Medium
#7
Type of
Molecule
4. Look back at all of the recorded properties for your 8 substances. What TRENDS do you see that might
group compounds together? For example, if something has a strong charge in water, is there a relationship to the
melting point?
Reflect and Connect pages 107 - 108
1. What does the word relative in the phrases relative hardness, relative melting point, and relative solubility
mean?
Use Figure 3.4 from page 107 below to answer the following questions: How would you classify each of the 3
compounds presented on Table 3.4? Justify your answers for each, based on evidence from the table:
What Kind of molecule is each of these substances? (Ionic, Polar, or Non-Polar)
Justify your answers for each based on evidence from the table below:
Compound
Artificial
Sweetener
Petroleum Jelly
Calcium Oxide
Appearance
White Powdery
Crystals
Greasy Solid
White Crystals
Hardness
Conductivity as
a solid
Solubility in
water
Melting Point
Yes
Conductivity as
a solution or
liquid
No
Medium Hard
No
Soft
Hard + Brittle
No
No
No
Yes
No
Strong
Low
High
Heat needed to
separate particles
Medium
2. Artificial Sweetener is a ______________________, because
3. Petroleum Jelly is a_____________________________, because
4. Calcium Oxide is a_____________________________, because
5. In which category would you place water? Explain why:
SIDEBAR: Electrical Conductivity pages 110 - 111 Read and fill in the table.
Word
conductors
insulators
electrical
conductivity
electric current
conductivity meter
electrolytes
Definition
(Book)
Description
(in your own words)
Image
(draw a picture)
Types of
Molecule:
Name it:
Real Examples
Compounds from
this Lab or other
Labs. Give more
than one
Ionic Molecule
_______________
______________
NaCl (give more)
Appearance and
Hardness
Why?
Form hard, brittle crystals,
because ionic molecules have
strong charges that hold them
together. To move them you
have to break up the charges.
Why?
Why?
Solubility in
Water
Why?
Soluble in water, because
ionic molecules are made of
ions that have strong charges
that water can attract and rip
apart the crystals with
Why?
Why?
Conductivity as a
Solution
Why?
Conduct strongly because
ionic molecules contain ions.
Why?
Why?
Melting Point
Why?
Have high melting points,
because their strong charges
hold the molecules together,
it would take a lot of heat to
rip them apart.
Why?
Why?