CHEMISTRY COMMUNITY

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The heme complex was essentially supposed to look like a chelate surrounding the iron atom in the middle, with four bonding sites to the cyanide molecules. The nitrogen could then attach to carbon-hydrogen compounds and form a more ring-looking complex.

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A titration, at least from what we've learned in class, is the addition of a base to an acid in solution (it can be the addition of an acid to a base as well, it just depends on the question) in such a way that enough base is added to the acid that the mole ratio is equivalent (or equal to 1). Then ...

gferg21

The stoichiometric point simply means that all of the acid had been reacted with an equivalent amount of base, and would didn't include any titration calculations, so it was not really a titration problem but more of a pH equivalence problem. I'm sorry if that tripped you up on the test.

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When an acid, base, conjugate acid, or conjugate base dissociates in water, the hydrogen will either be ejected from the conjugate acid or acid or will be accepted by the conjugate base or base. That is how you create H30+ and OH-.

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No, because salts do not affect the pH of a solution in any major way, and therefore cannot be "strong" or "weak."

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I think we are supposed to memorize the list of ligand bonding sites for different atoms that Lavelle sent us or it will be difficult to determine using the Lewis structures.

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cisplatin and oxaliplatin are the most common chemotherapy drugs and have four ligands, meaning that they are often in a square planar structure or a tetrahedral structure.

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Lewis bases are more likely to accept H+ ions to make a basic solution, whereas lewis acids are more likely to accept OH- ions to make a neutral solution

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We don't need to know the boiling and melting points of any solutions besides water, right?

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The acid and base concentrations of the formula add up to 14, so there may be a pH of 8, which means there is a pOH of of 6

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everything talked about in lecture should apply to all of the transition metals because they have very similar properties and would therefore form similar bonds.

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Hydrogen is always positive in an atom, so the electrons are going to be pulled away from it in a compound to make them more positive. This means that there will be polarity because the atom it is bonding to will be the one receiving the electron from hydrogen.

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hybridization is just counting the number of single (sigma) bonds and adding the number of double or triple (pi) bonds so find the hybridization number. If you can create the Lewis structure it will be easier to figure out.

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a ligand is any atom that con provide a pair of electrons for coordinate bonding, meaning that it donates an electron pair to create a bond.

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a sigma bond is the "first bond" that an atom makes to another, whereas pi bonds are the "second" or "third." If there is only a single bond then that is a sigma bond but if there is more than one there is a pi bond.

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the repulsion should be stronger when the electrons are closer together (closer to the nucleus), because of the atomic radius' role in coulomb's law.

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the molecular shape is the shape of a molecule as a whole, whereas electron geometry shows where in an atom an electron would be placed, and helps to determine the shape of an atom.

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the more electrons in the valence, the smaller the electron, the greater nuclear charge. That means that the atom has a higher electronegativity and will likely attract more electrons to it (or be more likely to accept and electron).

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the lone pairs take up more space in an atom than bonding pairs, and therefore repel each other while simultaneously repelling the bonding pair, causing a bent shape or distorted angle.

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The resonant structures should not have any impact on how the VSEPR structure is determined mostly because each of the resonant structures can be made into the same shape as the VSEPR (or at least look alike)

gferg21

The best way to do it is the first equation you put down. It needs less steps to figure it out, which could mean more time for questions on tests. The (b/2) seems a bit unnecessary but I understand that it is just to show that only one electron is actually the individual atom's.

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The octet rule is really only applicable to atoms in the s-orbital or in the periods 1 or 2. After the d-orbital is introduced, the expanded octet rule is applicable.

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Most of the time on tests (if needed) they will either give us the electronegativity of the the atoms or will add it to the periodic table. That way, the electronegativity is easier to find and we don't need to memorize them.

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In some compounds (such as water), molecules are attracted to each other with London dispersion forces, meaning that the electrons in the valence shell of the compound are attracted to the nuclei of the atoms of the other molecule. These forces are some of the weakest out of all of the bonding force...

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A dipole is a compound that has a difference in electronegativity between two different species of atoms, and the one with the higher electronegativity attracts the electrons to the atom, making one atom more negative and one more positive.

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triple bonds are the shortest bonds, double bonds are slightly longer, and single bonds are the longest.

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The most stable configuration of a molecule is the one with the lowest formal charge, so I would say to always draw the the most stable unless told otherwise.

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when the electrons in the electron cloud of the anion are attracted to the the nucleus of the cation in such a way that the cloud shifts toward the cation

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elements that have an open d- or f- orbital can have expanded octets, which means that atoms in the 3-shell and above can have expanded octets. When you calculate formal charge you just have to find the right arrangement of the atoms the formal charge will be the closest to zero or at zero.

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covalent bonds are not as powerful as ionic bonds, as covalent bonds share electrons to create a polar atom in many cases. Electronegativity plays a huge role in creating coordinate covalent bonds because one atom is sharing an entire lone pair with another atom, so the atom with the higher electron...

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resonance just shows different ways a compound can be configured, which is important to know when you have, say, one double bond and one single bond on a single central atom. It just shows that the compound's structure can be arranged many different ways.

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a lone pair is just that: a pair of lonely electrons just floating in the valence shell of an atom. Without an atom to bond to/share electrons with, they do not serve any major purpose at the moment besides showing that they are present.

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Only the central atom has 10 electrons in an expanded octet, and the d-orbital has a maximum of 10 electrons in it, so therefore the central atom can accept 5 single bonds.

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Atoms who have an open d-orbital (n is greater than or equal to 3) are able to accept 10 electrons because the d-orbital is able to hold 10 electrons rather than the usual 8. This only works for atoms of elements in the p-block, however.

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No, Cu and Cr are the only atoms in which the d shell is filled before the s shell because of the instability of the atom.

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Sometimes when atoms have multiple electrons they can lose them and end up with only one and a net positive charge. It's not super common but it can happen.

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because velocity has a speed of 3 x10^8 m/s, it is often used interchangeably with velocity because some equations need the speed of light. However, the direction of light is not specified with light.

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When writing electronic structure diagrams and assigning quantum numbers, it is useful to know that each sub-shell of the greater orbital can only hold two electrons, and the electrons must be "spinning" in opposite directions. For the ms quantum number you use -1/2 and +1/2 to indicate wh...

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The atoms of Cu and Cr are the most stable when they half of their shell can be filled, meaning that if the atoms did not receive that extra electron they would essentially be volatile, which is bad for an atom. The s-block is already filled in the periods 1-3, and therefore the s-orbital is fairly ...

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different orbitals have certain amounts of electrons that they can hold at a given time, and the x, y, and z planes essentially give a reference point to show where the electrons could be at a certain point. Electrons are constantly moving in a "cloud" around the nucleus, so the planes are...

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one of the most common units of wavelength is the nanometer (nm) because much of the visible spectrum of light falls within the range of 10^-9 meters.

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Because the electrons in the outermost shell have more room to move in the electron cloud, they have more energy and are less bogged down by the attractive forces from the nucleus and protons.

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Sometimes the wavelengths can overlap but they may not have the same amplitude, and will therefore not exactly double or exactly cancel out. In these cases there is still a wave present and not a "flat line" that you would see in a diagram.

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When talking about a vacuum, it essentially means that that is how fast light travels through space, and is very similar but not exactly the same on earth when light is traveling through the air.

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The mass of an electron is 9.11x10^-31 kg by the way. I know he mentioned it in lecture only once so some people may not have gotten it down.

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If there are zeros before the sig figs (like 0.0001), then all of the zeros are significant. If the number is an integer like 10, the zero is significant because there are no decimals. If it were 10.0, the last zero would not be considered to be significant unless specified by the question. If the n...

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When you look on the periodic table and see the mass of one carbon mole (12.011g) or another element, the number just means essentially how much mass a mole of that element is. One mole of carbon by itself is 12.011 grams, for example. it is just a simplified unit of measurement.

gferg21

lots of professors and textbooks will do this because it is easier to show with the exponent that it is m/s. I believe you also added both the "^-1" and the / in your question so it makes it look like a double negative. Hope this helps!

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What I believe it means by the white light being a mixture of all colors of light is that it does not have a specific wavelength because it is a mixture. There is no pure white light because it would be impossible to get every single color of light into one beam. Hope this helps!

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In a combustion reaction the only products are CO2 and H20 when a hydrocarbon is combusted. There are no combustion reactions that do not involve a hydrocarbon and therefore the products will always be CO2 and H20

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In the lecture slides there was a diagram that showed the different wavelengths of light, and highlighted particularly the visible spectrum of light and how small that particular segment was. My question is: can animals with more color cones in their eyes, such as eagles, see waves such as ultraviol...

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