Page 2 of 2 FirstFirst 12
Results 26 to 38 of 38
Like Tree2Likes

Thread: Phys/Chem Questions

  1. #26
    Junior Member _Anonymous's Avatar
    Join Date
    Jun 2017
    HSC
    2019
    Gender
    Male
    Posts
    132
    Rep Power
    1

    Re: Phys/Chem Questions

    There is also another question I have: H2O is a covalent molecular substance and is held together by Strong covalent bonds and weak intermolecular forces. Yet when we boil it, the intermolecular forces are gone but the covalent bonds still hold together the Hydrogen and Oxygen atoms. Whereas say for an Ionic or Metallic structure, when we boil/melt it - the ionic/metallic bonds also diminish resulting in the liquid/gaseous state. Even for Covalent network substances, once we melt it; the covalent bonds are gone and hence it's in a liquid form. I don't understand how covalent molecular substances can become liquid/gases if the Covalent bonds remain intact even after boiling/melting the substance.

    Also regarding the solubility of these substances. We know that when a Covalent Molecular substance dissolves in water, the atoms don't break apart from each other but rather stays together (i.e. if DiIodine dissolved, the Iodine molecules would still remain intact and not split apart). Whereas for Ionic compounds, once they dissolve in water; the ions are split apart and remain free as charged ions.

    My question is, say we have a soluble tablet (used as medication) dissolved in water, would the atoms being split apart (Ionic) have the same affect as the atoms being stuck together (Covalent molecular)? Do Scientists want the atoms to stick together so that the 'healing' properties of the tablet actually impacts the body or would the atoms being split apart have the same impact?
    Last edited by _Anonymous; 9 Dec 2017 at 7:03 PM.

  2. #27
    Split arrowhead ichila101's Avatar
    Join Date
    May 2016
    HSC
    2017
    Uni Grad
    2021
    Gender
    Male
    Location
    In Australia
    Posts
    212
    Rep Power
    2

    Re: Phys/Chem Questions

    Quote Originally Posted by _Anonymous View Post
    Anyone got answers to Q5 and Q6?
    some smart science uni students might help (maybe), but Ill make do for now
    Quote Originally Posted by _Anonymous View Post
    5) How does cutting of an object work in the molecular level? We know that metals don't break since the metallic structures prevent it to (Cations slide across a cushion of delocalised electrons). But say we had a metal-cutting band saw or something and managed to cut a piece of metal in half, how does that work? What would happen to the bonds? What caused them to break?
    I cant exactly recall metal being cut, however I do recall 1000 degrees Celcius knives on youtube cutting metal and that is simply because the metal is subject to high temperatures which melts it

    Quote Originally Posted by _Anonymous View Post
    6) Similar to Q5, Ionic compounds tend to be brittle. How come? Aren't their bonds strong due to the opposite charges attracting each other? I understand when a force is applied the ions displace and repel each other and that causes to break the structure, but why does that happen in the first place? Why is it so easy to displace the Cation and Anions if their bonds are so strong? How is a metallic structure's bonding stronger than one of an Ionic structure? Metallic structures are Cations surrounded by a sea of delocalised Electrons, wouldn't it be easier for them to vibrate more and break apart whilst Ionic bonds are more tightly held together by the Electrostatic attraction between the Cation and Anions, hence harder for it to vibrate and break (yet somehow Ionic compounds are brittle)?
    Brittle doesn't mean its weak it simply means it has a higher chance of breaking more easily however something can still be strong yet brittle. For example, the more calcium I drink, the stronger my bones get however the stronger my bones get the more brittle they get, its kind of like the opposite of flexible.

    Yeah ionic bonds are stronger than metallic bonds, what do you mean by displace? can you give an example if possible
    _Anonymous likes this.

  3. #28
    Split arrowhead ichila101's Avatar
    Join Date
    May 2016
    HSC
    2017
    Uni Grad
    2021
    Gender
    Male
    Location
    In Australia
    Posts
    212
    Rep Power
    2

    Re: Phys/Chem Questions

    Quote Originally Posted by _Anonymous View Post
    There is also another question I have: H2O is a covalent molecular substance and is held together by Strong covalent bonds and weak intermolecular forces. Yet when we boil it, the intermolecular forces are gone but the covalent bonds still hold together the Hydrogen and Oxygen atoms. Whereas say for an Ionic or Metallic structure, when we boil/melt it - the ionic/metallic bonds also diminish resulting in the liquid/gaseous state. Even for Covalent network substances, once we melt it; the covalent bonds are gone and hence it's in a liquid form. I don't understand how covalent molecular substances can become liquid/gases if the Covalent bonds remain intact even after boiling/melting the substance.

    Also regarding the solubility of these substances. We know that when a Covalent Molecular substance dissolves in water, the atoms don't break apart from each other but rather stays together (i.e. if DiIodine dissolved, the Iodine molecules would still remain intact and not split apart). Whereas for Ionic compounds, once they dissolve in water; the ions are split apart and remain free as charged ions.

    My question is, say we have a soluble tablet (used as medication) dissolved in water, would the atoms being split apart (Ionic) have the same affect as the atoms being stuck together (Covalent molecular)? Do Scientists want the atoms to stick together so that the 'healing' properties of the tablet actually impacts the body or would the atoms being split apart have the same impact?
    I think I mentioned this earlier not fully sure but anyways intermolecular bonds make up the physical properties of the compound, and because covalent compounds have intermolecular bonds those structures break and not the intramolecular ones. However ionic, metallic and covalent network all do not have any intermolecular bonds so their physical properties are created by their intramolecular bonds which is why this break instead

    They are completely different structures (since one is made up of ionic and the other is made up of covalent) hence they will have different impacts.

  4. #29
    Split arrowhead ichila101's Avatar
    Join Date
    May 2016
    HSC
    2017
    Uni Grad
    2021
    Gender
    Male
    Location
    In Australia
    Posts
    212
    Rep Power
    2

    Re: Phys/Chem Questions

    Quote Originally Posted by _Anonymous View Post
    There is also another question I have: H2O is a covalent molecular substance and is held together by Strong covalent bonds and weak intermolecular forces. Yet when we boil it, the intermolecular forces are gone but the covalent bonds still hold together the Hydrogen and Oxygen atoms. Whereas say for an Ionic or Metallic structure, when we boil/melt it - the ionic/metallic bonds also diminish resulting in the liquid/gaseous state. Even for Covalent network substances, once we melt it; the covalent bonds are gone and hence it's in a liquid form. I don't understand how covalent molecular substances can become liquid/gases if the Covalent bonds remain intact even after boiling/melting the substance.

    Also regarding the solubility of these substances. We know that when a Covalent Molecular substance dissolves in water, the atoms don't break apart from each other but rather stays together (i.e. if DiIodine dissolved, the Iodine molecules would still remain intact and not split apart). Whereas for Ionic compounds, once they dissolve in water; the ions are split apart and remain free as charged ions.

    My question is, say we have a soluble tablet (used as medication) dissolved in water, would the atoms being split apart (Ionic) have the same affect as the atoms being stuck together (Covalent molecular)? Do Scientists want the atoms to stick together so that the 'healing' properties of the tablet actually impacts the body or would the atoms being split apart have the same impact?
    I think I mentioned this earlier not fully sure but anyways intermolecular bonds make up the physical properties of the compound, and because covalent compounds have intermolecular bonds those structures break and not the intramolecular ones. However ionic, metallic and covalent network all do not have any intermolecular bonds so their physical properties are created by their intramolecular bonds which is why this break instead

    They are completely different structures (since one is made up of ionic and the other is made up of covalent) hence they will have different impacts.

  5. #30
    Junior Member _Anonymous's Avatar
    Join Date
    Jun 2017
    HSC
    2019
    Gender
    Male
    Posts
    132
    Rep Power
    1

    Re: Phys/Chem Questions

    Quote Originally Posted by ichila101 View Post
    I think I mentioned this earlier not fully sure but anyways intermolecular bonds make up the physical properties of the compound, and because covalent compounds have intermolecular bonds those structures break and not the intramolecular ones. However ionic, metallic and covalent network all do not have any intermolecular bonds so their physical properties are created by their intramolecular bonds which is why this break instead
    So is there way to break the Covalent bonds (intramolecular bonds) for Covalent molecular substances? If so, what would the outcome of it look like?

    Quote Originally Posted by ichila101 View Post
    They are completely different structures (since one is made up of ionic and the other is made up of covalent) hence they will have different impacts.
    Right, but what I'm trying to say is; would an Ionic substance (tablet) dissolved in water (with the result of free ions) have the same impact on the body as it would if the tablet was just swallowed instead (ionic bonds hold the opposing ions together) without any water?
    Last edited by _Anonymous; 10 Dec 2017 at 1:39 AM.

  6. #31
    Split arrowhead ichila101's Avatar
    Join Date
    May 2016
    HSC
    2017
    Uni Grad
    2021
    Gender
    Male
    Location
    In Australia
    Posts
    212
    Rep Power
    2

    Re: Phys/Chem Questions

    Quote Originally Posted by _Anonymous View Post
    Right, but what I'm trying to say is; would an Ionic substance (tablet) dissolved in water (with the result of free ions) have the same impact on the body as it would if the tablet was just swallowed instead (ionic bonds hold the opposing ions together) without any water?
    Yes, if both are the exact same (i.e. tablets) and all the water is consumed rhey will both have the exact same impact on the body, the only difference is it will be easier to swallow the one that is dissolved

    Sent from my SM-G900I using Tapatalk
    MX1/2U - ADV. ENGLISH - BIOLOGY - CHEMISTRY - BUSINESS STUDIES 2017
    No

  7. #32
    Junior Member _Anonymous's Avatar
    Join Date
    Jun 2017
    HSC
    2019
    Gender
    Male
    Posts
    132
    Rep Power
    1

    Re: Phys/Chem Questions

    Quote Originally Posted by ichila101 View Post
    some smart science uni students might help (maybe), but Ill make do for now

    I cant exactly recall metal being cut, however I do recall 1000 degrees Celcius knives on youtube cutting metal and that is simply because the metal is subject to high temperatures which melts it
    Oh, so the 'cutting' of metal is essentially just applying a lot of heat energy (through friction) and then melting it apart?

    Quote Originally Posted by ichila101 View Post
    Brittle doesn't mean its weak it simply means it has a higher chance of breaking more easily however something can still be strong yet brittle. For example, the more calcium I drink, the stronger my bones get however the stronger my bones get the more brittle they get, its kind of like the opposite of flexible.

    Yeah ionic bonds are stronger than metallic bonds, what do you mean by displace? can you give an example if possible
    Ahh right, I confused the definition of brittleness. Makes more sense with the definition below:

    A textbook I was going through stated this "If the ionic crystal is hit with an external force, the electrostatic attractions between the Cations and Anions can break (leading them to displace), allowing ions of like charge to line up and repel. Thus the crystal will fracture". I guess this explains its brittleness?
    Last edited by _Anonymous; 10 Dec 2017 at 1:47 AM.

  8. #33
    Split arrowhead ichila101's Avatar
    Join Date
    May 2016
    HSC
    2017
    Uni Grad
    2021
    Gender
    Male
    Location
    In Australia
    Posts
    212
    Rep Power
    2

    Re: Phys/Chem Questions

    Quote Originally Posted by _Anonymous View Post
    Oh, so the 'cutting' of metal is essentially just applying a lot of heat energy (through friction) and then melting it apart?



    Ahh right, I confused the definition of brittleness. Makes more sense with the definition below:

    A textbook I was going through stated this "If the ionic crystal is hit with an external force, the electrostatic attractions between the Cations and Anions can break (leading them to displace), allowing ions of like charge to line up and repel. Thus the crystal will fracture". I guess this explains its brittleness?
    Yeah kind of, brittleness is a comparative term so its simply the measure of how easy it is for the ionic crystal to displace. If there is a high chance of it displacing then it is really brittle however if there is a low chance of it displacing then it isnt really that brittle

    Sent from my SM-G900I using Tapatalk
    _Anonymous likes this.
    MX1/2U - ADV. ENGLISH - BIOLOGY - CHEMISTRY - BUSINESS STUDIES 2017
    No

  9. #34
    Junior Member _Anonymous's Avatar
    Join Date
    Jun 2017
    HSC
    2019
    Gender
    Male
    Posts
    132
    Rep Power
    1

    Re: Phys/Chem Questions

    Quote Originally Posted by ichila101 View Post
    Yeah kind of, brittleness is a comparative term so its simply the measure of how easy it is for the ionic crystal to displace. If there is a high chance of it displacing then it is really brittle however if there is a low chance of it displacing then it isnt really that brittle

    Sent from my SM-G900I using Tapatalk
    Do you know whether Covalent compounds (Covalent Molecular & Covalent Network substances) are brittle or not? If they are, how does that work (in terms of molecular level)?

  10. #35
    Split arrowhead ichila101's Avatar
    Join Date
    May 2016
    HSC
    2017
    Uni Grad
    2021
    Gender
    Male
    Location
    In Australia
    Posts
    212
    Rep Power
    2

    Re: Phys/Chem Questions

    Quote Originally Posted by _Anonymous View Post
    Do you know whether Covalent compounds (Covalent Molecular & Covalent Network substances) are brittle or not? If they are, how does that work (in terms of molecular level)?
    I dont think you can give covalent compounds a level of brittleness since thet just vary way to much. Like covalent compounds like H2O and CH4 are not brittle at all because they arent even solid they are liquids and gases respectively. The case is the same with covalent network, if we compared graphite with diamond, we would say graphite could break really easily though this certainly isnt the case for diamond

    Sent from my SM-G900I using Tapatalk
    MX1/2U - ADV. ENGLISH - BIOLOGY - CHEMISTRY - BUSINESS STUDIES 2017
    No

  11. #36
    Junior Member _Anonymous's Avatar
    Join Date
    Jun 2017
    HSC
    2019
    Gender
    Male
    Posts
    132
    Rep Power
    1

    Re: Phys/Chem Questions

    Quote Originally Posted by ichila101 View Post
    I dont think you can give covalent compounds a level of brittleness since thet just vary way to much. Like covalent compounds like H2O and CH4 are not brittle at all because they arent even solid they are liquids and gases respectively. The case is the same with covalent network, if we compared graphite with diamond, we would say graphite could break really easily though this certainly isnt the case for diamond

    Sent from my SM-G900I using Tapatalk
    Yeah, but let's say when we freeze the above mentioned compounds. Ice is quite brittle (frozen water).

  12. #37
    Split arrowhead ichila101's Avatar
    Join Date
    May 2016
    HSC
    2017
    Uni Grad
    2021
    Gender
    Male
    Location
    In Australia
    Posts
    212
    Rep Power
    2

    Re: Phys/Chem Questions

    Quote Originally Posted by _Anonymous View Post
    Yeah, but let's say when we freeze the above mentioned compounds. Ice is quite brittle (frozen water).
    Sorry yeah in that case ice is pretty brittle, however noble gases for example cannot be frozen so they do not have a brittle property.

  13. #38
    Junior Member _Anonymous's Avatar
    Join Date
    Jun 2017
    HSC
    2019
    Gender
    Male
    Posts
    132
    Rep Power
    1

    Re: Phys/Chem Questions

    Quote Originally Posted by ichila101 View Post
    Sorry yeah in that case ice is pretty brittle, however noble gases for example cannot be frozen so they do not have a brittle property.
    So since Ice is brittle, what's the reasoning behind that in the molecular level? I get the intermolecular forces are weak, but the Covalent bonds are strong. To break the structure, do the intermolecular forces only need to be broken? Is there any reasoning like the Ionic compounds (where same charges repel each other and break the crystal)?

    If Covalent bonds don't need to be broken for the structure to change, then what purpose do they serve by holding the atoms together? For example, you said that a solid tablet (let's use NaCl for simplicity) would have the same effect as the Na+ and Cl- ions which are free in the water (dissolved state). So relating back to that same example, if we were to have H2O (in liquid state) where the Covalent Bonds are broken and the Hydrogen and Oxygen atoms are roaming free in that liquid structure, wouldn't it be the same as drinking normal water (where Covalent bonds hold the Hydrogen and Oxygen atoms together)?

    Also, will we learn why Noble gases cannot be frozen in Yrs 11/12? I saw something related to it being unpolarised and other terms I'm unfamiliar with.
    Last edited by _Anonymous; 13 Dec 2017 at 12:14 AM.

Page 2 of 2 FirstFirst 12

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •