Search found 25 matches
- Sun Jun 10, 2018 12:04 am
- Forum: Bronsted Acids & Bases
- Topic: 12.17
- Replies: 1
- Views: 425
Re: 12.17
I think you find out whether it is an acidic, basic, or amphoteric oxide by looking at the periodic table as illustrated in the diagram below. Hope this helps!
- Sat Jun 09, 2018 11:07 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molar Mass
- Replies: 5
- Views: 858
Re: Molar Mass
The grams per mole value (i assume you mean molar mass) would be 32gmol^-1 if you're converting from grams to moles for O2.
- Sat Jun 09, 2018 11:00 pm
- Forum: Hybridization
- Topic: sigma vs pi bonds
- Replies: 4
- Views: 855
Re: sigma vs pi bonds
I hope this comparison table helps!
Sigma bonds have a head on overlap compared to pi bonds which overlap sideways. Pi bonds also restrict rotation while sigma bonds allow free rotation around the bond.
Sigma bonds have a head on overlap compared to pi bonds which overlap sideways. Pi bonds also restrict rotation while sigma bonds allow free rotation around the bond.
- Sun Jun 03, 2018 3:00 pm
- Forum: Dipole Moments
- Topic: Different types of dipole moments?
- Replies: 3
- Views: 512
Re: Different types of dipole moments?
A dipole moment is when atoms in a molecule share electrons unequally. This occurs when one atom is more electronegative than another. By different types, do you mean a dipole-dipole and dipole-induced-dipole interaction? Dipole dipole is a type of intermolecular attraction, which is a attraction be...
- Sun Jun 03, 2018 2:42 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands
- Replies: 8
- Views: 1341
Re: Ligands
Ligands are lewis bases that donate a lone pair to the central transition metal in a complex to form a coordinate bond. That is why it needs at least one lone pair of electrons or it has no lone pair to donate to the central atom.
- Sun Jun 03, 2018 2:40 pm
- Forum: Hybridization
- Topic: Hybridization
- Replies: 3
- Views: 511
Re: Hybridization
Hybridization is the mixing of atomic orbitals to form new orbitals with different energies and shapes than the original orbitals. I think the mixing of the different types of atomic orbitals allows the atom to form more equal energy bonds and thus the result is a more stable molecule. To determine ...
- Sun May 27, 2018 11:47 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge Exponent
- Replies: 5
- Views: 1048
Re: Formal Charge Exponent
Hello, I am not too sure what your question means but I think the overall charge on a molecule like SO4^2- means when you add up all the formal charges of the individual atoms in the molecule, the final answer should equal 2-. For example (just an example!), if all the formal charges of O is 0 but S...
- Sun May 27, 2018 11:38 pm
- Forum: Octet Exceptions
- Topic: 3.61
- Replies: 4
- Views: 4697
Re: 3.61
ICl4- has 36 electrons in total. You first form a skeletal structure (with iodine (least electronegative atom) as your central atom)and so there are 4 single bonds connecting the iodine to each chlorine and that means you used up 8 electrons (28 e- left). You then add 6 electrons to each chlorine at...
- Sun May 27, 2018 11:30 pm
- Forum: Ionic & Covalent Bonds
- Topic: Most covalent or ionic character
- Replies: 3
- Views: 1725
Re: Most covalent or ionic character
Most covalent means the difference in electronegativity between the two atoms in a molecule is small while most ionic means the difference in electronegativity is big between two atoms.
- Mon May 21, 2018 12:08 am
- Forum: Dipole Moments
- Topic: lone pairs
- Replies: 3
- Views: 471
Re: lone pairs
I believe it is only the shared electrons that will have partial charges due to differences in electronegativity which contributes to dipole moments. Therefore, I don't think lone pairs contribute towards dipole moments.
- Mon May 21, 2018 12:07 am
- Forum: Lewis Structures
- Topic: How do I start a Lewis structure?
- Replies: 3
- Views: 648
Re: How do I start a Lewis structure?
The least electronegative atom should be the central atom. You then draw the skeletal structure of the molecule by adding a single bond to connect all atoms in the molecule together. You then subtract this from the total number of valence electrons you have. You can then try to arrange the valence e...
- Sun May 20, 2018 11:47 pm
- Forum: Ionic & Covalent Bonds
- Topic: Octet rule
- Replies: 17
- Views: 2443
Re: Octet rule
Q: When we do break the octet rule, is there any specific way to add electrons? A: After the third period/row, the octet rule can be broken because of the electrons in the d-block. There is no specific way to add electrons I believe. It is just counting the number of total valence electrons and tryi...
- Sun May 20, 2018 11:23 pm
- Forum: Electronegativity
- Topic: Electronegativity vs. Electron affinity
- Replies: 7
- Views: 841
Re: Electronegativity vs. Electron affinity
To answer your second question, the central atom is usually the atom with the lowest electronegativity as the central atom is the one that shares more electrons than the non-central atoms. The higher the electronegativity, the less the atom wants to share electrons with another atom. Therefore, the ...
- Sun May 13, 2018 6:23 pm
- Forum: Lewis Structures
- Topic: Lewis Structure [ENDORSED]
- Replies: 3
- Views: 452
Re: Lewis Structure [ENDORSED]
I think there really isn't a way to know beforehand. The first step is to count valence electrons available in the molecule and then the second step is to attach the atoms to each other with single bonds to form a skeletal structure. From then on, it kind of is trial and error. You just have to plac...
- Sun May 13, 2018 5:57 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charge purpose
- Replies: 40
- Views: 7240
Re: Formal charge purpose
Yes, it is desirable for molecules to have the lowest energy lewis structure possible so that it can have the most stable structure. The lower the formal charge for the molecule overall and also for the individual atoms themselves, the more stable the structure.
- Sun May 13, 2018 5:53 pm
- Forum: Resonance Structures
- Topic: Bonds or Lone Pairs more important?
- Replies: 7
- Views: 1127
Re: Bonds or Lone Pairs more important?
I don't think there is a general rule as to whether you should add lone pairs or double bonds between atoms to the central atom to achieve a stable octet of electrons. It just depends on the molecule itself and what would make a structure with the lowest formal charge possible for the lewis structur...
- Sun May 06, 2018 9:15 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic radii and ionization energy
- Replies: 1
- Views: 282
Re: Atomic radii and ionization energy
Atomic energy decreases across a period because there will be constantly an addition of 1 proton versus an addition of 1 electron, and the strength of the pull of the proton on the electrons (electrostatic attraction) will outweigh the electron repulsion between electrons, hence, the radius of an at...
- Sun May 06, 2018 2:10 pm
- Forum: Photoelectric Effect
- Topic: Test #2 Question 7 [ENDORSED]
- Replies: 2
- Views: 453
Re: Test #2 Question 7 [ENDORSED]
The question asks for the max wavelength or lowest energy, meaning when you shine the light on the metal surface, an electron just gets enough energy to be popped out onto the surface of the metal, but there will not be any extra energy for the electron to have kinetic energy. Therefore, you should ...
- Sun May 06, 2018 2:04 pm
- Forum: Trends in The Periodic Table
- Topic: The Ionization energy of Oxygen
- Replies: 2
- Views: 314
Re: The Ionization energy of Oxygen
The general trend is ionization energy increases across a period due to the increased pull from the nucleus (+ve charge) as you are adding electrons to the same principal shell so it will be harder to remove electrons across the period. However, oxygen is one of the exceptions. This is because nitro...
- Sun Apr 15, 2018 7:53 pm
- Forum: SI Units, Unit Conversions
- Topic: L35, What is t? (Conversion)
- Replies: 3
- Views: 483
Re: L35, What is t? (Conversion)
Yep, I am pretty sure t stands for ton, and the conversion is 1000kg= 1 ton(t)
- Sun Apr 15, 2018 7:52 pm
- Forum: SI Units, Unit Conversions
- Topic: writing out conversions in one long line vs. steps
- Replies: 16
- Views: 1488
Re: writing out conversions in one long line vs. steps
If you're talking about unit conversions within the same step, I would write it out in one long line to make sure I know which units are cancelling with which. However, if there are different separate steps required for the problem, I would write it out in steps to present my work more clearly durin...
- Sun Apr 15, 2018 7:47 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Which mass of oxygen should be used? [ENDORSED]
- Replies: 23
- Views: 3381
Re: Which mass of oxygen should be used? [ENDORSED]
Good practice would be to use 15.999. But in exam conditions, when you might not have enough time to type in a lot of decimal places/digits, I asked my TA and she mentioned that she would not deduct points as long as your working out is correct and showed and also as long as the final answer is very...
- Sun Apr 15, 2018 7:43 pm
- Forum: Balancing Chemical Reactions
- Topic: Balancing Chemical Equations and Combustion
- Replies: 7
- Views: 1022
Re: Balancing Chemical Equations and Combustion
Combustion reactions will always have carbon dioxide (CO2) and water (H20) as its products. Whatever substance is being combusted with will always react with oxygen to be combusted (i.e. O2 will always be a reactant). You can then balance your equation normally.
- Sun Apr 15, 2018 7:38 pm
- Forum: SI Units, Unit Conversions
- Topic: Length Units
- Replies: 15
- Views: 1532
Re: Length Units
Yes, you should use SI units unless otherwise specified explicitly in the question.
- Sun Apr 15, 2018 7:36 pm
- Forum: SI Units, Unit Conversions
- Topic: Avogadro's Number [ENDORSED]
- Replies: 11
- Views: 1429
Re: Avogadro's Number [ENDORSED]
I believe avogadro's number can be used to convert both from moles to atoms and from moles to molecules.