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LAB: Properties of Ionic and Covalent Compounds 

Crash Chemistry Academy
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This is a virtual lab video I prepared for my students (linked below). The lab looks at four properties of each of nine compounds: 1. appearance & state of matter at room temperature; 2. solubility in water; 3. conductivity; 4. melting time. In the linked lab doc the idea is to determine which properties best predict whether a compound is ionic or covalent.
This is the lab document I prepared that goes with the video: docs.google.com/document/d/1Q...

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24 ноя 2020

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Комментарии : 41   
@LOL-wr7mp
@LOL-wr7mp 2 года назад
hello. great video! but i have a question, what are the conductivity units in µS/cm of each substance in video? thank you!
@j3tr110
@j3tr110 Год назад
What's the independent variable in this experiment.
@aesarahypatia3482
@aesarahypatia3482 3 года назад
nice! great lab doc, great vid.
@dslmlgpro7004
@dslmlgpro7004 3 года назад
Hey man from Trinidad and have a question what is the name of the electrical tool in the vid thanks and please keep up the grate work.
@CrashChemistryAcademy
@CrashChemistryAcademy 3 года назад
As far as I know it is just called a conductivity tester
@robertmarks6525
@robertmarks6525 3 года назад
Thank you sir
@ci8007
@ci8007 3 года назад
This is very nice! But I have a question. I searched it up and saw that Hydrogen Chloride is a covalent compound, and most of the covalent compounds do not conduct electricity since they do not contain ions. Though, except for some of its solid state such as graphite. If this is the case, how come that the HCl is a conductor of electricity? Please enlighten me, thank you!❤️
@CrashChemistryAcademy
@CrashChemistryAcademy 3 года назад
Good question. The answer is the same for all acids. HCl becomes an acid when dissolved in water, meaning it loses H+ when dissolved, leaving Cl-. The reason the two atoms dissociate as ions in water is because 1) hydrogen has no shielding--only a single electron that spends most of its time closer to the chlorine due to the large electronegativity difference, meaning hydrogen's nucleus (a single proton) is very exposed to the water, and 2) because water is so polar (it has a negative side, the oxygen, and a postive side, the hydrogens) it attracts that exposed proton (+ charge) off the chloride, resulting in two ions, H+ and Cl-. It is the ions in water that are able to conduct electricity. The water is not very good at taking H+ away from acetic acid, which is why acetic acid conducts poorly compared to HCl, as seen by the light bulb being dimly lit from aqueous acetic acid.
@ci8007
@ci8007 3 года назад
@@CrashChemistryAcademy Thank you very much, sir!
@CrashChemistryAcademy
@CrashChemistryAcademy 3 года назад
@@ci8007 you're welcome!
@hirastic
@hirastic 9 месяцев назад
Answer to the question asked at the end of the video: since benzoic acid and hcl have low melting point, they are already liquid and gas at room temperature. Hence, their M.P is lower than 27°C. So, they have less M.P than the solids shown in the video.
@familiatill5499
@familiatill5499 2 года назад
very good video. Anybody here for chemistry class?
@kaylaward3606
@kaylaward3606 2 года назад
yeeesss lol and it's due tonight :(
@ntl_3j810
@ntl_3j810 Год назад
@@kaylaward3606 me right now
@fartcrap6366
@fartcrap6366 4 месяца назад
Unfortunately
@therealdefoma
@therealdefoma 8 месяцев назад
When you tested pure distilled water, why did the lightbulb not light? I thought that water was a really good conductor?
@CrashChemistryAcademy
@CrashChemistryAcademy 8 месяцев назад
Water is a poor conductor. In order to conduct electricity in a fluid, ions (charged particles) must be present. The amount of ions in pure water is approximately 2 ions for every ten million molecules of water. This makes for a poor conductor. HOWEVER, water is really great at dissolving ions, like sodium ions and chloride ions (etc) from dissolved salt, and so it is those ions moving through the water that allows a current to flow. This would happen in the bathtub when you throw in the toaster to electrocute your little brother: The tap water has some ions, your skin has salt on it that gets dissolved in the bath water, and dissolved soap molecules are ions. This makes for a very conductive situation.
@nurulain8990
@nurulain8990 2 года назад
hi. May i know if Acteic acid have high or low melting point? all i found is about their boiling point
@joelweiner5877
@joelweiner5877 2 года назад
It has a relatively low melting point. It is already a liquid at room temperature. It is about 15 Celsius.
@escapeyourreality-relaxing2041
@escapeyourreality-relaxing2041 3 года назад
Hey i did these for fun, I was wondering where the answers were?
@SkittlesScott
@SkittlesScott 3 года назад
right
@fabianralph5472
@fabianralph5472 2 года назад
May I ask how to solve the compound's conductivity in units of S/m
@CrashChemistryAcademy
@CrashChemistryAcademy 2 года назад
I believe S/m is a unit resistivity, which can be converted from conductivity. Although I do not know how to calculate resistivity (or conductivity) in these solutions, I assume a volt/ohm meter would give you the numbers needed to convert. I can tell you that conductivity is entirely dependent on the amount of dissolved ions per unit volume solution (higher concentration = higher conductivity) and likely the amount of charge on the ions is relevant since the conductivity is dependent on the oxidation-reduction happening at the electrodes. Regarding the conductivity of the compound itself (your question), you would have to melt the compound and test its conductivity in the liquid state, which for ionic compounds is likely going to be very high since the ions are not dispersed in water, in other words, very concentrated.
@fabianralph5472
@fabianralph5472 2 года назад
@@CrashChemistryAcademy Thank You Doctor. I have an experimental output using your video but it needs the units to be in S/m. Luckily there is a table for that in the internet. One last question. According to my research HCl ( in liquid form) has almost 0.01 conductivity. However it conducts strong electric conductivity in this video. What are your thoughts about it sir.
@fabianralph5472
@fabianralph5472 2 года назад
@@CrashChemistryAcademy Ohh I get it.. HCl(hydrogen chloride) can be Hydrochloric Acid which has a great electric conductivity than Hydrogen Chloride.
@CrashChemistryAcademy
@CrashChemistryAcademy 2 года назад
Yes. HCl, although quite polar, does not carry charge, and so is a poor conductor. When HCl is dissolved in water, it becomes hydrochloric acid. What that means is the HCl is producing H+ and Cl- ions in solution. That is what makes it an acid. Since you now have charged particles in solution that are able to move, that means they can carry a current. Because HCl is so good at splitting into ions when dissolved, it is a very good conductor because it contributes many ions per mole of ions dissolved-- one mole of dissoved HCl will produced almost one mole of H+ and almost one mole of Cl- ions.
@AbsoluteArtist
@AbsoluteArtist 3 года назад
Which bond is stronger ?
@CrashChemistryAcademy
@CrashChemistryAcademy 3 года назад
There is no division of bond strength between ionic and covalent. In general, ionic bonds are strong, meaning they require a lot of energy to break. But covalent compounds have an extremely wide range of bond strengths, from very weak (takes little energy to break) to very strong (takes a great deal of energy to break. A couple examples: the bond energy between the carbons of diamond are extremely high, while the bond energy between carbon and nitrogen in nitroglycerin is very low. Most covalent compounds fall in between these extremes and are often quite similar to ionic bond energies.
@atticus2329
@atticus2329 3 года назад
nerd
@ischl420
@ischl420 2 года назад
@@atticus2329 ??
@alam9756
@alam9756 3 года назад
Thank you 🙏 greetings from iraq 🇮🇶
@CrashChemistryAcademy
@CrashChemistryAcademy 3 года назад
شكرا لك. أبعث بتحياتي إلى العراق!
@joyskingdom588
@joyskingdom588 3 года назад
@@CrashChemistryAcademy you know arabic?
@CrashChemistryAcademy
@CrashChemistryAcademy 3 года назад
@@joyskingdom588 لا ، أنا أستخدم مترجم جوجل
@zoomrusher9598
@zoomrusher9598 3 года назад
cool
@harshmenon599
@harshmenon599 2 года назад
fool
@ischl420
@ischl420 2 года назад
@@harshmenon599 ??
@nurizatiabdulaziz1755
@nurizatiabdulaziz1755 3 года назад
Thank you sir
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