CHEMISTRY COMMUNITY

Alex Hitti 3E

You can determine which acid is stronger by Bond Length and anion stability. The longer the bond length, the stronger the acid. The more stable a molecule is the stronger the acid. Oxoacids work a little differently: the more Oxygens, the higher the electronegativity of the central atom, and the hig...

Alex Hitti 3E

It doesn't matter which way you write it, though you can write it from positive to neutral to negative charge. And if you encounter 2 atoms of the same charge then you can go by alphabetical.
Good to know: Metals are always put first when going from name to formula

Alex Hitti 3E

A polyprotic acid can donate more than one proton, while a polyprotic base can accept more than one proton. Also, a good thing to know about polyprotic acids is that the acid becomes weaker after each proton it donates. For example, H2SO4 + H2O -> HSO4- + H3O+ and HSO4- + H2O -> SO4(-2) + H3O+ H2SO4...

Alex Hitti 3E

No, bond lengths are what determine strong acids (long) and weak acids (short). Also the rule that it'll be weak if it has an extra H won't suffice because H2SO4 dissociates to HSO4- and it is still a strong acid. A weak acid is usually organic compounds whihc have C and H.

Alex Hitti 3E

It is a chelating ligand which binds 6 times thus it is a hexadentate

Alex Hitti 3E

Strong acids and bases are 100% ionized when reacted. Weak acids and bases are less than 100% ionized. Strong acids produce more protons than their weak counterpart while strong bases produce more hydroxide ions than weak bases.

Alex Hitti 3E

The conjigate acid is the molecule that gains a proton when a base is added into a solution Ex. NH3 + H20 -> NH4+ + OH- The rxn can be broken down like this, respectively: base + acid -> conjugate acid + conjugate base In this rxn H20 acts as an acid though it has a neutral pH. Water can act as an a...

Alex Hitti 3E

To find the oxidation number of a TM:
1) take the sum of all the oxidation numbers of each component bound to the central TM atom
2) find the overall charge of the molecule (usually given)
3) subtract the overall charge by the sum of all oxidation numbers stated in part 1

Alex Hitti 3E

Yes because, for example, all Bronsted are Lewis but not all Lewis are Bronsted.

Alex Hitti 3E

The coordination number of an atom in a molecule is the number of atoms bonded to the atom. For Cu+, it would simply be the possible amount of atoms that it could bond to. The coordination number represents the number of bonds the central atom has in a molecule. In regards to Cu+, the coord # would ...

Alex Hitti 3E

Heme complex is the central atom iron that is bound to a ligand with a tetradentate structure (which binds to the iron is 4 different places) which binds to a protein structure and an oxygen molecule (O2). Its biological importance helps carry oxygen throughout the blood and cells.

Alex Hitti 3E

The biological importance for transition metals surrounds the oxidation states of the TM for electron transfer. A few examples include
chromium: assists in control of blood sugar
iron: myoglobin, hemoglobin, e- transfer in the oxidation of carbohydrates, proteins, fats

Alex Hitti 3E

How do you find the oxidation state of transition metals in a coordination compound?

Alex Hitti 3E

Bronsted refers to hydrogen donors (acid) and acceptors (base). Meanwhile, lewis refers to lone pair donors (base) and acceptors (acid).

Alex Hitti 3E

cis- means that the electronegative atoms are both on one side which creates a dipole moment. meanwhile trans- means that the electronegative atoms are on opposite sides whicgh the dipole moments cancel out, thus there is no dipole moment. In regards to cis/trans-platin, the chlorine atoms are the p...

Alex Hitti 3E

London Dispersion Forces (and van der Waals) are temporary attractive forces that occur when very slight opposing charges are adjacent for a brief amount of time to create short-lived dipoles. Induced dipole - induced dipoles can be referred to as LDF/van der Waals because of this.

Alex Hitti 3E

Concept: The stronger the bond, the higher the boiling point.

From highest to lowest boiling point:

ion - ion
ion - dipole
hydrogen bond
dipole - dipole
induced dipole - dipole
induced dipole - induced dipole

Alex Hitti 3E

Ion-dipole, LDF, and dipole-dipole, etc are intermolecular forces: forces between two different molecules meanwhile polar/nonpolar are intramolecular forces (within the molecule).
Also, dipole-dipole: interactions between 2 polar molecules
LDF: interactions between 2 non polar molecules

Alex Hitti 3E

The larger the molecule means a greater amount of electrons to be polarized, and therefore a stronger induced dipole-dipole moment?

Yes, the molecular size is proportional to the strength of the dipole moment. As one increases, so does the others.

Alex Hitti 3E

Yes! Hydrogen bonding is a special form of dipole-dipole forces with hydrogen bonding exhibiting stronger intermolecular forces. This is because H (low EN) is paired with N,O, or F (high EN)

Alex Hitti 3E

A Chlorine-Hydrogen bond cannot form hydrogen bonds because Cl has too large of a radius, thus creating an electron density not sufficient enough to form Hydrogen bonding.

Alex Hitti 3E

HNO2 is the only ones that will form Hydrogen bonds because there is a greater electronegativity difference between O and H thus making it polar / able to form H-bonds. In the case of Br, Br is too large to have enough electronegativity to pull the electrons more than the H can. H has to bind to a h...

Alex Hitti 3E

Double bonds are shorter in length than single bonds because they are stronger and harder to break apart due to the atoms sharing more electrons and a greater attraction.

Alex Hitti 3E

How do you know if a molecule is polar or not so you can state whether it is a dipole-dipole or london dispersion? A dipole-dipole interaction between molecules alludes that the molecule is polar while london dispersion forces alludes to the molecular interactions being non polar. An interaction, in...

Alex Hitti 3E

A triple bond consists of one sigma bond and one pi bond

Alex Hitti 3E

Sigma bonds are the initial bond between 2 atoms and as more bonds (double & triple bonds) form, each bond (except for one) is considered an added pi bond. for example, a double bond would be 1 sigma bond and 1 pi bond; and a triple bond would be 1 sigma bond and 2 pi bonds. sigma bonds are also...

Alex Hitti 3E

If an atom has an incomplete d and 3(+)p orbital(s) in period 3 and down, they can have an expanded valence shell. In the Lewis dot diagram, the number of electrons do not really go past 12, which fortunately helps for space & convenience's sake.

Alex Hitti 3E

No, we don't have to memorize the octet exceptions. But it's good to know (not relating to "exceptions") that only atoms in row 2&3 maxes at 8 valence electrons because in row 4, for example, they have more space in their d block.

Alex Hitti 3E

Electronegativity is the tendency to gain an electron meanwhile electron affinity is the energy released when an electron is transferred to an anion

Alex Hitti 3E

Only the 2nd row in the periodic table can have a maximum of 8 valence electrons because it has the 2s and 2p orbitals

Alex Hitti 3E

In a simpler observation (not including any calculations), ionic bonds are bonds between a metal and nonmetal where electrons are donated/transferred. Meanwhile, covalent bonds are bonds between 2 non-metals where electrons are shared. Ionic bonds also tend to have a high boiling point and a large p...

Alex Hitti 3E

In natural life, covalent bonds are stronger than ionic bonds due to the natural aqueous state that surrounds us. Because ionic bonds become weak when placed in water/polar-aqueous solution. In a theoretical "dry/non-aqueous" world, ionic bonds are stronger than covalent bonds. In other wo...

Alex Hitti 3E

Double headed arrows is the symbol that implies that the reaction is reversible. If an arrow is pointing only one way then that implies that the reaction is nonreversible.

Alex Hitti 3E

Xe can form bonds because it has a very large atomic radius compared to other noble gases meaning that the ionization energy of the atom for the outermost electrons is relatively minimal, minimal enough to allow it to create bonds with atoms that have relatively high electronegativity.

Alex Hitti 3E

Ionic bonds are bonds between a metal (cation) and a nonmetal (anion) and the cation donates the electron to the anion because of the large difference in electronegativity and ionization energy. Meanwhile, covalent bonds are between two nonmetals and they share the electron(s) by the electron transf...

Alex Hitti 3E

It tends to depend on personal preferences and through trying different strategies to see which one clicks the most. Personally, what really helps me is going over youtube videos/his modules and doing many practice problems to get the routines down and know when to use which formula depending on wha...

Alex Hitti 3E

I think it isn't working because there is a small error in your formula.
The equation for kinetic energy: KE = (0.5)*mass*velocity^2.
Also, another equation you will need later on: ΔxΔp >= h/(4pi)

Alex Hitti 3E

Scientists found out that 4pi is a constant that is consistent whenever using the formula. If you want a more specific answer, Dr. Lavelle said that to discover this we have to fully understand the derivation of the equation which is a long and tedious process since most of the information we haven'...

Alex Hitti 3E

During my discussion, the TA said that for anything that has mass (like electrons), we should use the equation: wavlength = h/(mv)
Meanwhile, anything that doesn't have mass (like photons), we use the equation: wavelength = c/(frequency)
mass of electron = 9.11 * 10^-31 kg

Alex Hitti 3E

Dr. Lavelle generalized the concept so I wouldn't use that equation since there are more complicated and accurate ways to achieve the derivation. He said to not worry about it too much since it won't be a main focal point in the midterms and finals.

Alex Hitti 3E

The energy of a photon = (planck's constant) * (speed of light) / wavelength
I think this is probably the closest that you can get to what you are looking for.

Alex Hitti 3E

For anyone else wondering, the mass of an electron is about 9.11 × 10^(-28) grams.

Alex Hitti 3E

How can we determine if the problem is asking for a wave model or a photon model?

Alex Hitti 3E

When atoms absorb energy, the electrons go into an "excited" state which moves them up electron orbitals. In short, when an atom is excited, electrons have absorbed energy.

Alex Hitti 3E

Planck's constant is critical as a constant because it relates the energy of a photon to its frequency.

Alex Hitti 3E

There is an acronym for visible light from longest to shortest wavelength is ROY-G-BIV (red, orange, yellow, green, blue, indigo, violent). I don't know any acronyms for the rest but the general graph/chart from shortest to longest is: gamma rays, x-rays, ultraviolet, visible light (ROY-G-BIV backwa...

Alex Hitti 3E

A polar molecule is when there are slight positive and/or negative charges within the atoms. This is formed when one of the atoms tends to attract the electrons more than the others due their electronegativity levels. Hydrogen and Carbon tend to have low electronegativity levels that is why all hydr...

Alex Hitti 3E

What is the difference between the electric and magnetic fields? In other words, what are the electric and magnetic fields and what role does each of them play?

Alex Hitti 3E

I use variables to associate all of the coefficient together with. Usually, I assign the most complex compound the variable 'x' then I go step by step linking the other molecules to 'x'. And then I assign them the coefficient that all the different molecules had for 'x'. And for what is left (or doe...

Alex Hitti 3E

Oxygen, Hydrogen, Sulfur, Sodium, and Phosphorus walk into a bar.
The bartender exclaims "OH SNaP!"

Alex Hitti 3E

It's always better to show work than not because you can earn at least partial credit even though you may have got the answer wrong by making an incorrect step/calculation.

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