- CHEMISTRY REPORT -
Conductivity of Ionic and Polar Covalent
Bonds in Different States of Matter
= CRITERIA B =
Scientific Question & Aim
Does being different states of matter affect the conductivity of ionic and polar covalent bonds? The aim of this experiment is to find out what happens to the conductivity of ionic and
polar covalent bonds while being in different states of matters (solid, liquid, aqueous).
Hypothesis
a) Solid Form
For both covalent and ionic compounds, I predict that when both compounds are in a solid
form, they will not be able to conduct electricity.
This hypothesis is supported by an article from
yeahchemistry.com as well as many other articles, that mention how ionic compounds that are in solid form are unable to conduct electricity because to conduct electricity, the electrons within the compound has to be free to move around, and being in a solid form restricts that freedom. Other than that, another article (also from yeahchemistry.com) mentioned that there are two keys to electric conductivity, which are (1)
there must be charged particles and (2) those charged particles should be able to move around freely. The reason the electrons are not free is because the energy level structure does not provide anywhere for the electrons to go to. An unoccupied energy level is required in order to enable the movement of electrons, in that case.
b) Liquid Form
After researching about the conditions that is required for a compound to be able to conduct electricity well, I predict that being in a liquid form
will enable the ionic compound to adequately conduct electricity. The ionic bond will be able to
conduct electricity because it has moving ionic properties, it has full filled the criteria of electric conductivity.
I also predict that being liquid also allows the
polar covalent bond to conduct electricity even if it’s just a small amount of conductivity. If it were to
be non-polar however, it wouldn’t be able to conduct electricity. As a chemistry teacher who answers students’ questions has mentioned in socratic.org, either moving electrons or moving ions are required in conductivity, in which non-polar covalent bonds have neither. Metals (in ionic bonds)’s delocalized bonding makes it capable of conducting electricity, while covalent bonds have localized bonds, meaning that electrons don’t
Solid Form Compounds
Liquid Form Compounds
move. Alright, how about moving ions? Well, covalent bonds are not made of ions, if they were they’d be called ionic compounds, which means that non-polar covalent bonds are for sure not going to be able to conduct electricity.
However, I’m dealing with a polar covalent bond. The reason why I think that it is capable of conducting electricity is because polar covalent bonds have unequally shared electrons between atoms, and the atom with the stronger electron pull (resulting in higher electronegativity) would have the shared electrons closer to it, hence the inequity. This will cause the molecule to have a slightly more positive side and a slightly more negative side, and that means that the molecule has a potential in being electrostatic. It may be weak in its job, but it’s possible.
c) Aqueous Form
Many sources have stated that the aqueous
form should be the most successful in conducting
electricity. In an article about conductivity and bonds (sciencenotes.org), it is said that polar covalent bonds do dissolve in water and do conduct
electricity. Hydroiodic acid and hydrochloric acid, for example, are strong acids who disassociates into ions in water. So, according to this article, polar
covalent bonds are capable of conducting electricity when in water, but it is not so strong.
Other than that, many polar covalent compounds
have hydrogen as the cation (it is known from the first symbol of the formula).
Hydrogen’s associated to being labeled as a nonmetal, but on the periodic table, it’s with the alkali metal group. A polar covalent bond that contains hydrogen and other non-metals would be almost ionic but is still not.
This hypothesis is testable and it is not too much of a challenge to test, because all the materials that I have chosen are simple, easy to find, and safe to use. To summarize the hypothesis, here is a table of all of them combined:
Electric Conductivity Effectiveness
Solid Form Liquid Form Aqueous Form
NaCl + KIO3 Non-Conductive Conductive (Strong) Conductive (Strong)
Variables
Independent Variable
An independent variable is the factor in an experiment that has been changed or manipulated so the effects of the manipulation can be recorded and concluded. The independent variable of this experiment are the type of compounds that are used. In this case, the independent variables include the polar covalent bond, represented by sucrose (C12H22O11), and the ionic bond, represented by sodium chloride (NaCl). The credibility
of NaCl as the representative of ionic bonds for this experiment is acceptable because many of the articles I’ve read chose NaCl to explain the concept of ionic compounds in their specific topics. The credibility of C12H22O11 is also enough for it to represent the
whole polar covalent compound category, as it is also widely used as an example in articles that I’ve read to explain polar covalent bonds, written as “Sugar”. The reason that these compounds are the independent variable and not the state of matters is because the dependent variable’s measurement results depend on the properties and factors of the compounds more than they depend on the differences of the states of matter. Other than that, the understanding of electric conductivity in different states of matter are more likely to stay the same with any other compounds of the same kind.
Dependent Variable
The dependent variable is the factor in the experiment that is measured or tested. For this experiment, what I’ll be measuring and testing will be the electric conductivity of both the polar covalent bond and the ionic bond. It will be measured with the help of a multimeter, and will be measured with Volt as the unit. The electric current that I’m dealing with is an alternating current because the multimeter only responds to the electric flow when it is set to AC-V (Alternating Current Voltage), at the scale of 10V. The battery provides an initial voltage of 1.5V, for every test that is done, it must be in between the scale of 0-1.5V on the multimeter. The effectiveness of conductivity (percentage) for each compound in each state of matter should be measured by dividing the voltage that appears on the multimeter and then dividing it with 1.5 and then
multiplying it with 100.
Control Variable
The control variables are the factors in an experiment that are kept the same, in other words, constant. In this case, there are a lot of control variables involved. First, there is the mass of the compounds. The compounds will each be measured to 50 grams or 50ml for every state of matter and compound. I will make sure that the measurements are all correct by using a scale and a beaker glass.
attachments to the battery do not alter so that all the states of matter for each compound will experience the same tests.
Third, the equipment and their conditions will remain the same. What I mean is that the stove, beaker glass, spatula, multimeter, and other tools will remain the same kind, size, and temperature. For the making of the aqueous solution and liquid state, the water that is used to water bathe the compounds should also be the same amount, starting time, and starting temperature. The end temperatures depend on the melting point of each compound, I will make sure that the compounds will end at the same density.
Fourth, the states of matter will remain the same. Not to be mistaken with the independent variable, the states of matter (solid, liquid, aqueous) counts as a control variable because it is kept the same for both independent variables. For the solid form, I will make
sure that both compounds have similar physical states, thankfully both start of as white-translucent, odorless, little crystalline shaped substances. For the liquid form, both compounds will take the same method (water-bathing) to transition it from solid into liquid. For me to be able to get the proper aqueous form of the compounds, the ratio of the water and the compound should be 1:1 so that it is equal.
Fifth, the method of liquefying the compounds will stay the same. For both compounds, they will be put in a beaker glass and then the beaker glass is put into a sauce pan/pot that has already been filled up by 300ml of water. The starting temperature of the water used will be the same, along with the temperature of the beaker glasses.
The time of observation will be different because sucrose (chosen polar covalent bond) and table salt (NaCl) have different melting points. However, I will still record the time it takes to melt the two compounds. Therefore, it is not considered as a control variable.
Materials
a) Compounds:
Polar Covalent Bond (C12H22O11)
The covalent bond that I will be using for my experiment is C12H22O11
(Sucrose). Sucrose is common among disaccharides. Disaccharides are sugars that are made out of two monosaccharides (simple sugar compounds). In this case, sucrose is a combination of glucose (C6H12O6,
blood sugar) and fructose (also C6H12O6) a fruit sugar
that is often found bonded with glucose. It usually comes in a form of white, odorless, crystalline shape.
The reason why I’ve chosen this covalent bond is because it is very easy to find, as it is found in sugarcane sugar we use at home. I had a bit of trouble looking for an adequate example of a covalent bond that would be capable of being in the
three states of matter that will be used in this experiment (solid, liquid, aqueous) but is also easy to find. At first I thought of rubbing alcohol (C3H7OH), it’s easy
to find, but then I realized that it is volatile and cannot be converted into a solid state easily, which makes it impractical for this experiment. Ammonia also came into mind, until I found out that it is also volatile. I then concluded that the sugar at home is an acceptable compound for this experiment.
However, there are a few limitations that comes with this decision. After further research from multiple credible sources, it can be concluded that sucrose is an organic polar compound that is not ionic. It can be called as polar because of the presence of multiple hydroxyl groups in it, and that enables it to make hydrogen bonds with water, making sucrose soluble. With that being said, the
conclusion of this experiment cannot apply to non-polar compounds, it only applies to a few other weak polar covalent bonds.
It would have been better if there were a polar covalent bond that is easy to find and safe to use and that is a strong polar covalent bond, that way the results would be more apparent, however so far sugar is a decent enough
representative. Sucrose has a melting point of 186°C, which means when I heat it up to melt it, it shouldn’t take so long until it starts to liquefy.
Ionic Bond (NaCl + KIO3)
The ionic bond that I chose for this experiment is NaCl (sodium chloride, table salt). NaCl is a very common omnipresent ionic
compound that can be found in the salt that we use in everyday food and usages. It usually comes in a solid crystalline form, and it is odorless and translucent. It has a melting point of 801°C, which means it may take very long to melt.
The reason why there is KIO3 (Potassium
Iodate) is because, like most other table salts that are sold in supermarkets, Potassium Iodate is used to stabilize the NaCl. I have decided to use table salt as a representative of ionic bonds for this
experiment because it is the easiest ionic compound to find around the house, and that it is safe and stable.
b) Additional Ingredients:
Water (H2O)
In this experiment, water is used to indirectly melt the compounds and it is also used to dissolve the compounds so that I can get the aqueous solutions of the compounds. According to a forum between chemistry teachers and a website called sciencenotes.org, the water we use in our daily lives is capable of weakly conducting electricity, but that’s because of the salutes that it contains. Pure water itself is a polar covalent bond, and contrary to popular belief, pure water is
capable of conducting electricity, but it is extremely weak. However, pure water is almost impossible to get, because pure H2O because it dissociates into the ions
OH- and H+. When it is used to make an aqueous substance, it is most likely that it is able to conduct electricity.
c) Equipment:
Beaker Glass (small, 100ml)
Stove (to liquefy the compounds)
Multimeter (to measure the electric conductivity of the compounds)
Spatula/Spoon (to stir the dissolved compounds)
Boiling Pot (to liquefy the compounds)
Wires (15cm in size for both ends of the battery
Batteries (size AA, 1.5V, Alkaline brand).
Safety
Since I’m dealing with heat and electricity, there are some things that has to be done to prevent the unwanted from happening, which are:
Making sure that I am wearing my lab coat properly to protect myself.
Keeping my work station neat and clean (wipe the table and the equipment with rubbing alcohol to sterilize them).
Keep my hands clean by washing them beforehand and after the experiment.
Making sure that my workspace is safe for working with fire, keeping away flammables from the fire in the process of the experiment.
Make sure that after I expose glass to hot temperature, I don’t immediately expose it to cold temperature because that could lead to the glass shattering.
Method
a) Solid State Observation
1. Put 50g of cane sugar into one beaker glass and 50g of table salt to the other, both being in the state of its original form, little crystalline.
2. Attach both rods of the multimeter into the ionic compound, then to the polar covalent compound.
3. Write down the results of observation.
b) Liquid State Observation
1. Prepare the saucepan/pot and filling it up with 300ml of tap water of room temperature.
2. Put 50g of the ionic compound into the beaker glass. 3. Put the beaker glass into the saucepan/pot.
4. Turn on the stove, with medium height.
5. After the compound melts, it is taken out and set aside, change the water into new tap water and wait for 5 minutes to cool down the saucepan.
6. Doing step 1-4 with the other compound with the same heat.
7. After that, set it aside and attach both rods of the multimeter into the ionic compound, then to the polar covalent compound.
8. Write down the results of observation.
c) Aqueous State Observation
1. Prepare the compounds from the “Liquid State Observation”.
2. Add 50ml of hot water of the same temperature to both compounds. 3. Stir well, until compounds are completely dissolved in the water. 4. Wait for 10 minutes, until the solutions cool down.
5. Attach both rods of the multimeter into the ionic compound, then to the polar covalent compound.
6. Write down the results of observation.
= CRITERIA C =
Results
During the process of heating the sugar and salt, I recorded the time to see how long it would take to get it from solid into a molten-liquid state. With a medium temperature on the stove, the sugar (C12H22O11) took about 30 minutes to liquefy. It had a very thick texture to it and
acted a lot like what it is, liquid caramel. On the other hand, Table Salt (NaCl + KIO3) took about
2 hours to melt. It takes very long because it has a very high melting point of 801°C, and in the end the texture and consistency of the salt was very condensed and thick, making it more molten than liquid. Here is a table for all the results, along with a picture. The green highlight means that the results are aligned with what I have hypothesized, and the red highlight means that the results don’t exactly align with the hypothesis.
Electric Conductivity (V)
Solid Form Liquid Form Aqueous Form
NaCl + KIO3
Non-Conductive
Effectiveness: 0
1.5× 100 = 𝟎%
1.5 Volts (Conductive Strong)
Effectiveness:1.5
1.5× 100 = 𝟏𝟎𝟎%
/
1.5 Volts (Conductive Strong)
Effectiveness:1.51.5× 100 = 𝟏𝟎𝟎% C12H22O11 Non-Conductive Effectiveness: 0 1.5× 100 = 𝟎% Non-Conductive Effectiveness: 0 1.5× 100 = 𝟎%
1 Volt (Conductive Weak)
Effectiveness: 1
1.5× 100 = 𝟔𝟔%
Conclusion
After commencing the experiment in my kitchen, I found out that the ionic compound, NaCl + KIO3 (table salt) is not conductive when it is solid because the electrons are not able to
move around. The same goes with the polar covalent compound, C12H22O11 (Sucrose), it is
In the liquid form, the ionic compound was able to conduct electricity very well, while the polar covalent bond was unable to conduct electricity. This may be due to the transport of electrons being far too weak to get to the other end of the wire, and since it was in a very thick substance it may have very slow transport speed, the polar covalent bond is only capable of little conductivity in this state of matter and the voltage was low in the first place so it couldn’t compensate with what is required for conductivity.
References
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