GRADE 8 SCIENCE
IONIC AND COVALENT COMPOUNDS LAB INVESTIGATION
Background
We know that atoms bond to each other. Scientists have found that there are only three types of
bonds: ionic bonds, covalent bonds, and metallic bonds. If atoms have an ionic bond, the solid
they make is called an ionic compound. If atoms have a covalent bond, the solid they make is
called a covalent compound.
B Research Question
What are the physical properties of ionic compounds and covalent compounds?
C Variables
Complete the following table with 3 constant variables for each experiment.
Experiment
1
Independent Variable
Dependent Variable
Smell
2
Melting point
3
Microscopic structure
4
Ionic and covalent
solid
Hardness
5
6
Solubility
Electrical conductivity
7
Flame test
Constant Variables
Distance from nose, have the same
amount. You smell it softly or hardly.
Temperature, amount and time of the
chemical
Distance
Light settings
Type of lens.
Type of material , amount of solid,
distance from solid
Amount, temperature of water and
Type of material ,light bulb, same
amount.
Hardness of ionic and covalent solid
Amount of solid.
Distance from solid
D Hypothesis
Complete these statements for the six properties you are testing. A good hypothesis will help you to
write a good conclusion.
If a solid has strong bonds between its atoms, then
 the smell will be strong because of the type of the chemicals
 the melting point will be higher because of the mixture that it hold on.
 the microscopic structure will be different because of the formation of difference size.
 the hardness will be stronger because two different atoms come together with form a new
bonds
 the solubility will be strong because the bonds are strong.
 the electrical conductivity will be strong because of the strong bonds between the atoms that
cause the electrons move faster.
E Equipment and Materials
You will need all of this equipment at one point in the investigation. Collect only the equipment you
need for each new experiment.


Lab coat (to wear throughout the practical investigation)
Safety glasses (to wear when appropriate - you choose when and your teacher will check!)
 Sodium carbonate (ionic compound)
 1 microscope
 Naphthalene (covalent compound)
 4 test tubes
 Pen for labeling glass containers
 Water
 2 spatulas
 2 small glass beakers
 1 watch glass
 1 lamp
 2 test tubes and test tube holder
 1 ammeter
 2 test tube tongs
 1 battery or power supply pack
 Spirit burner or Bunsen burner
 3 electrical cables
 Stopwatch
 2 carbon electrodes
 2 microscope slides
 2 flame-test-sticks
F Method and G Diagram
Work carefully through each experiment. Record your observations carefully after every experiment.
Experiment 1: Smell
1. Use a spatula to place a sample of each solid on a watch glass.
2. Observe and record your observations.
Experiment 2: Melting Point
1. Put 2 spatulas of each solid in a test tube (use two separate test tubes).
2. Heat each test tube for the same amount of time until one of the solids melts.
3. Continue heating them for three more minutes.
4. Observe and record your observations.
Experiment 3: Microscopic Structure
1. Place a sample of each solid on a microscope slide.
2. View the solid under the microscope
3. Observe and record your observations.
Experiment 4: Hardness
1. Attempt to crush some of each solid on the watch glass using the spatula.
2. Observe and record your observations.
Experiment 5: Mixing with other Liquids
1. Put 2 cm of water (an ionic liquid) into 2 different test tubes.
2. Add a spatula-tip of each solid to separate test tubes (use one test tube for each solid).
3. Observe and record your observations.
4. Put 2 cm of 2-propanol (a covalent liquid) into 2 different test tubes.
5. Add a spatula-tip of each solid to separate test tubes (use one test tube for each solid).
6. Observe and record your observations.
Experiment 6: Electrical Conductivity
1. Construct an electrical conductivity tester similar to the diagram (use a power supply instead of
a battery and add an ammeter in series with the lamp)
2. Half-fill 2 beakers with water
3. Stir a spatula tip full of each solid into separate beakers (use one beaker for each solid).
4. Observe and record your observations.
Experiment 7: Flame Test (Just for Fun! – Not really to do with ionic and covalent solids)
1. Put a small amount of each solid on the flame-test-stick and hold each solid in a flame.
2. Observe and record your observations.
H Observations
You have lots of results to report. Design a clear table that has no sentences in it and give the table
an informative title. Insert your table and title here.
Observation of the seven experiments.
1,smells
2.Melting point
A. It smells
like soap
that to use
to wash the
clothes
b. no smell
A.8 seconds
b.5 minutes
and 38
seconds(hasn’t
even melt.)
3.Microscopic
Structure
A. looks like
small ices.
4.hardness
5.Solubility
a.There is
hardness
A. Not
soluble
B.looks like
crystal
B.no
hardness
B. Quite
soluble.
6.Electricity
Conductivity
A. No
conduct to
the
electricity
7.Flame
test
A. Flame
turn black
B. it
conducts
electricity
B. The
flame is still
the original
colour.
I Presenting and Processing Data (Not required in this investigation)
J Conclusion
Insert your conclusion here.
1. Answer the research question.
2. State whether your results support your hypothesis.
3. Do some research about the strength of ionic and covalent bonds and explain why the ionic
compound showed the properties it showed, and why the covalent compound showed the
properties it showed.
In my investigation I have discovered the different smells , which one mets faster,is it harder or
not, does it conducts electricity and the flame color. The results in my experiments supports my
hopothesis because in my investigation it shows that when we see it with a microscope it looks
different , is it hard or not. The strength of ionic bond is much stronger that covalent bond
because ionic bond has + and – so it sticks, but covalent bond it has the same charges. Ionic
compound must show the properties because if not, it cannot connect electricity.
K Evaluation (Not required in this investigation)
L Real Life Application
Add two real life applications of ionic compounds and two real life applications of covalent compounds
here. You may not use the examples given in your textbook – find something else!
The two real life application are that sodium hydroxide makes soap and silicone dioxide
which makes glass. The two real life application of a covalent compounds are CO2, its used
to extinguish the fire and Water (H2O) is used in everyday life.
M.Works Cited
"What Are the Properties of Covalent Compound?" Yahoo! Answers. Yahoo!, n.d. Web. 13 Feb. 2013.
Strengths of Covalent Bonds." Strengths of Covalent Bonds. N.p., n.d. Web. 13 Feb. 2013.
N.p., n.d. Web.
"Ionic vs Covalent Bond Strength | MCAT Study Question Q&A | Student Doctor Network." Student
Doctor Network Forums RSS. N.p., n.d. Web. 13 Feb. 2013.
Criterion B: Communication in Science
Student’s Teacher’s
Opinion Decision
SWA MYP Descriptor

0


1–2



3–4



5–6

The student does not reach a
standard described by any of the
descriptors given below.
The student uses a limited range of
scientific language correctly.
The student communicates scientific
information with limited
effectiveness
When appropriate to the task, the
student makes little attempt to
document sources of information.
The student uses some scientific
language correctly.
The student communicates scientific
information with some
effectiveness.
When appropriate to the task, the
student partially documents
sources of information.
The student uses sufficient scientific
language correctly.
The student communicates scientific
information effectively.
When appropriate to the task the
student documents the sources of
information correctly.
Student Self-Assessment
 My work does not match requirements below.
 I used some scientific language.
 For most sections of the lab report I followed
most of the requirements listed on the task
sheet.
 I give some info for some of my sources.
 I used only scientific language.
 For each section of the lab report I followed
most of the requirements listed on the task
sheet.
 Source information is missing making it hard for
the reader to trace my sources
 I used clear, concise, scientific language.
 For each section of the lab report I followed
completely the requirements listed on the task
sheet.
 I correctly cite my sources of information in text
and with a Works Cited list.
Criterion E: Processing Data
Student’s Teacher’s
Opinion Decision
0
SWA MYP Descriptor

The student does not reach a standard
described by any of the descriptors given
below.

My work does not match the
requirements below.

The student collects some data and
attempts to record it in a suitable format.
The student organizes and presents
data using simple numerical or visual
forms.
The student attempts to identify a trend,
pattern or relationship in the data.
The student attempts to draw a conclusion
but this is not consistent with the
interpretation of the data.
The student collects sufficient relevant
data and records it in a suitable format.
The student organizes, transforms and
presents data in numerical and/or visual
forms with some errors or omissions.
The student interprets the data stating a
trend, pattern or relationship in the data.
The student draws a conclusion
consistent with the interpretation of the
data.
The student collects sufficient relevant
data and records it in a suitable format.
The student organizes, transforms and
presents data in numerical and/or visual
forms logically and correctly.
The student correctly interprets the data
stating a trend, pattern or relationship in
the data.
The student draws a clear conclusion
consistent with the correct
interpretation of the data and explains
it using scientific reasoning.

Some of my data is relevant and my
table is partly correct

I tried to make a conclusion.

My data is relevant and recorded in a
suitable way.
I try to organize and process the data.
My conclusion matches the observations.

1–2




3–4




5–6
Student Self-Assessment




 My data is relevant and my presentation
is logical and clear.
 I correctly interpret the data.
 In my conclusion I comment on the
reliability of my data through comparing
my results to what would be expected
from published data.
 I give a scientific explanation of my
conclusion.
Criterion F: Attitudes in Science
Student’s Teacher’s
Opinion Decision
0
1–2
3–4
5–6
SWA MYP Descriptor
 The student does not reach a standard
described by any of the descriptors given
below.
 The student requires some guidance to
work safely and some assistance when
using material and equipment.
 The student requires some guidance to
work responsibly with regard to the living
and non-living environment.
 When working as part of a group, the
student needs frequent reminders to
cooperate with others.
 The student requires little guidance to
work safely and little assistance when
using material and equipment.
 The student works responsibly with
regards to the living and non-living
environment.
 When working as part of a group, the
student cooperates with others on
most occasions.
 The student requires no guidance to
work safely and use materials and
equipment competently.
 The student works responsibly with
regards to the living and non-living
environment.
 When working as part of a group, the
student cooperates with others.
Student Self-Assessment









My work does not reach a standard
described by any of the descriptors
given below.
During the experiment I did not know
what to do.
I forgot safety routines such as wearing
goggles, standing up, etc.
During the experiment I asked
questions even though the answer to
the question was provided in writing
and orally beforehand.
I forgot safety routines such as wearing
goggles, standing up, etc.
I did not ask questions that had already
been answered in writing.
I knew what I was doing in the lab
I included safety precautions in my
report and followed all safety routines
responsibly during the experiment.
I worked well with classmates.