Name:
Date:
Period:
Properties of Ionic Compounds Lab (35 pt)
Introduction:
The goal of this lab is for you to investigate some of the properties of ionic and compounds. The physical
properties of a substance such as flame color, crystal structure, solubility, conductivity, and melting point of a
substance tell us a lot about the type of bonding in a compound. The electrostatic force that holds oppositely
charged particles together in an ionic compound is referred to as an ionic bond!
Properties of Compounds
Ionic Compounds
Crystal Lattice
Soluble in water and alcohol (not oil)
High Melting Point
Conductive as aqueous, not solids
Covalent Compounds
Often soft or brittle
Many soluble in oil but not in water
Lower Melting Point
Do not conduct electricity
In this experiment, you will conduct tests on the physical properties of different compounds and compile data
enabling you identify ionic compounds and covalent compounds based on their properties.
Objective: Investigate the properties of ionic and covalent compounds.
Safety: Goggles and hair ties are required for this lab. Keep paper and clothing away from flame.
Materials:
Samples of compounds
Plastic minicups & tops
Sugar
Microscope
Distilled Water
Bunsen Burner
50mL graduated cylinder
Conductivity testers
Crucible Tongs
100mL beakers
Toothpicks
Four Ionic Compounds to Test:




Sodium Chloride (NaCl)
Copper (II) Sulfate (CuSO4)
Potassium Chloride (KCl)
Magnesium Sulfate (MgSO4)
Three Covalent Compounds to Test:



Corn Starch (C27H48O20)
Sugar (C6H12O6)
Flour(C4H8O4)
Pre-Lab Questions (10 pts):
Read the introduction and procedure before answering the following questions:
1. What kinds of elements generally form ionic compounds (metals, non-metals, metalloids)?
2. What kinds of elements generally form covalent compounds (metals, non-metals, metalloids)?
3. Based on the type of elements involved, predict whether each of the following compounds are
primarily ionic or covalent. (Hint: Look for the elements on the periodic table to see if they are metals,
nonmetals, or metalloids)
a. Sodium Chloride (NaCl): ____________________________
b. Copper (II) Sulfate (CuSO4): _________________________
c. Potassium Chloride (KCl): ___________________________
d. Magnesium Sulfate (MgSO4): ________________________
e. Sugar (C6H12O6): ___________________________
f. Flour (C4H8O4): ____________________________________
g. Cornstarch (C27H48O20): _________________________
4. In your own words, write the purpose of the experiment. (What are we trying to achieve?)
Procedure:
Station 1: Crystalline Structure
Materials: 5 microscopes, 5 petri dishes with various samples
1. Do not touch any knobs on the microscopes, they will already be focused for you.
2. Next to each microscope, there is a petri dish with one of the following compounds: KCl, MgSO 4, CuSO4,
NaCl, sugar, cornstarch, and flour.
3. In your table, draw a picture of what you see in the microscope and write detailed observations. Circle
whether the compound formed a crystal lattice or not.
Station 2: Test for Conductivity of solid ionic compounds
Materials: 4 petri dishes, copper strip, conductivity tester, samples of solids
1. At the station, you will find 8 beakers each with the different solids to investigate.
2. Turn the conductivity tester on and ensure that it is working by testing the conductivity of a copper
strip. Red light only = tester is working, red & green together = conducts electricity.
3. Test the conductivity of your solids by placing the tester into each pile. Clean the ends of the tester
between each test.
4. Record your findings on Data Table 2.
Station 3: Flame test
Materials: small beaker with each solution, toothpicks, Bunsen burner
1. Make sure all long hair is secured back with a hair tie and all loose clothing is secure
2. Turn on the gas to the Bunsen burner and light carefully with a lighter
3. Using tongs, take one toothpick from a beaker and hold over the flame. Observe the color of the flame.
4. Once the color changes to a yellow or you smell burning wood, take toothpick out of flame and
carefully blow out. Discard toothpick in the beaker labeled “Trash”
5. Record color on Data Table 3
6. Turn the gas off.
Station 4: Solubility Materials: distilled water, samples of various compounds, 50 mL graduated cylinder,
beakers, stopwatch, spoon
1. Measure half a spoonful of each sample into 8 small labeled beakers
2. Add 15 ml of distilled water to each using the graduated cylinder.
3. Slowly swirl the beaker. Time how long it takes the substance to dissolve, using a stopwatch. Repeat
for all substances. Record the time in Data Table 4.
4. Record the solubility level as either: Completely / Partially / Insoluble in Data Table 4.
5. Rinse beakers.
Station 5: Conductivity of Aqueous Solutions
Materials: Distilled water, beakers of each solution, conductivity meter.
(DO NOT DUNK THE TESTER IN THE DI WATER BEAKER, RINSE WITH THE JUG OF DI WATER IN THE SINK OR
RESULTS WILL BE COMPROMISED).
1. 9 beakers will be labeled with distilled water and all compounds.
2. Test the conductivity of distilled water by turning the tester on and lowering it into the beaker of
distilled water. Red light only = tester is working, red & green together = conducts electricity
3. Record below whether or not it conducted electricity in Data Table 5;
4. Test the other 5 solutions for conductivity.
5. Be sure to rinse and dry the metal contacts between each test with the beaker of distilled water).
6. Record below whether conductivity as high, low or none in Data Table 5.
7. Rinse distilled water beaker only.
Date Tables: (15 pts)
Data Table Station 1:
Station 1: Crystalline Structures Data Table
Compound
Observations
Potassium Chloride (KCl)
Crystalline or Not (circle one)
Copper (II) Sulfate (CuSO4)
Crystalline or Not (circle one)
Sodium Chloride (NaCl)
Crystalline or Not (circle one)
Sketch
Magnesium Sulfate (MgSO4)
Crystalline or Not (circle one)
Sugar (C6H12O6)
Crystalline or Not (circle one)v
Flour (C4H8O4):
Crystalline or Not (circle one)
Cornstarch (C27H48O20)
Crystalline or Not (circle one)
Data Table Station 2:
Station 2: Conductivity of Solids
Compound
Potassium Chloride (KCl)
Copper (II) Sulfate (CuSO4)
Sodium Chloride (NaCl)
Magnesium Sulfate (MgSO4)
Sugar (C6H12O6)
Flour (C4H8O4):
Cornstarch (C27H48O20)
Data Table Station 3
Conductive or Not Conductive
Station 3: Flame Test Data Table
Compound
Color of Flame
Potassium Chloride (KCl)
Copper (II) Sulfate (CuSO4)
Sodium Chloride (NaCl)
Magnesium Sulfate (MgSO4)
Sugar (C6H12O6)
Flour (C4H8O4):
Cornstarch (C27H48O20)
Data Table Station 4:
Station 4: Solubility Data Table
Compound
Time to
Dissolve
Solubility
Distilled water
(control)
Compound
Magnesium
sulfate (MgSO4)
Time to
Dissolve
Solubility
Completely
Partially
Insoluble
Sodium
Chloride (NaCl)
Potassium
Chloride(KCl)
Copper (II)
Sulfate
(CuSO4)
Completely
Sugar (C6H12O6)
Completely
Partially
Partially
Insoluble
Insoluble
Completely
Flour (C4H8O4)
Completely
Partially
Partially
Insoluble
Insoluble
Completely
Partially
Insoluble
Cornstarch
(C27H48O20)
Completely
Partially
Insoluble
Data Table 5: Conductivity of Aqueous Solutions
Station 5: Conductivity of Aqueous Solutions
Compound
Distilled water
(control)
Conductivity
Compound
Conductivity
None
Magnesium
sulfate (MgSO4)
None
Low
High
Sodium Chloride
(NaCl)
Potassium
Chloride(KCl)
Copper (II) Sulfate
(CuSO4)
None
Low
High
Sugar (C6H12O6)
None
Low
Low
High
High
None
Flour (C4H8O4)
None
Low
Low
High
High
None
Low
High
Cornstarch
(C27H48O20)
None
Low
High
Analysis Question (2 pts)
1. Look up the melting points for each of the five solids and record the values in the below table. Review the
relative melting point of each of the compounds. Are these high melting points or low?
Compound
Melting point (oC)
High or Low?
Potassium Chloride (KCl)
Copper (II) Sulfate (CuSO4)
Sodium Chloride (NaCl)
Magnesium Sulfate (MgSO4)
Sugar (C6H12O6)
Flour (C4H8O4):
Cornstarch (C27H48O20)
Conclusion Questions ):
1. Complete the table below by looking back at your previous data tables (5pt)
Chemical
formula
Potassium
Chloride (KCl)
Copper (II)
Sulfate (CuSO4)
Sodium
Chloride (NaCl)
Magnesium
Sulfate
Crystal
structure
or Not
Conductivity
as a Solid
Crystal
structure
or Not
Yes or No
Crystal
structure
or Not
Crystal
structure
or Not
Crystal
structure
or Not
Yes or No
Yes or No
Yes or No
(MgSO4)
Sugar (C6H12O6)
Flour (C4H8O4):
Cornstarch
(C27H48O20)
Crystal
structure
or Not
Crystal
structure
or Not
Crystal
structure
or Not
Yes or No
Yes or No
Yes or No
Flame
test color
Solubility
(Soluble,
Insoluble, or
Partially)
Conductivity
as Aqueous
Soluble
None
Insoluble
Low
Partially
High
Soluble
None
Insoluble
Low
Partially
High
Soluble
None
Insoluble
Low
Partially
High
Soluble
None
Insoluble
Low
Partially
High
Soluble
None
Insoluble
Low
Partially
High
Soluble
None
Insoluble
Low
Partially
High
Soluble
None
Insoluble
Low
Partially
High
Ionic or
Covalent
Compound?
2. Did the properties of compounds found in our lab experiment match the expected properties listed
on the first page of the lab? Use observations or information from question 1 to support your
answer (3-5 sentences) (3pt)
3. What are some things we could have done differently to give more accurate results? If you got
results in question 2 inconsistent with the properties on the first page of the lab, be sure to explain
why you think your results were different and what could be done differently. (3-5 sentences) (4pt)
4. List the expected properties of ionic compounds. (3pt)
5. List the expected properties of covalent compounds. (3pt)