CHEMISTRY COMMUNITY

Gustavo_Chavez_1K

This would only apply to gases, not liquids

Gustavo_Chavez_1K

The formula is the (equilibrium constant/initial concentration of HA) x 100%

Gustavo_Chavez_1K

I would say that the only and probably easiest way is to just memorize the list of strong acids and bases. With this all the acids and bases that aren't listed as strong would be considered weak.

Gustavo_Chavez_1K

I remember in lecture Lavelle saying that if the k value is 10^-4 or smaller then x can be omitted in the E section of the ICE table.

Gustavo_Chavez_1K

The larger the Ka value, the stronger the acid. The larger the Kb value, the stronger the base.

Gustavo_Chavez_1K

Yeah I would say that the memorizing the list of strong acids and strong bases would help out a lot for this. Since if they are not on the list then they are automatically considered weak. Well weak in comparison to the listed strong acids and bases.

Gustavo_Chavez_1K

We are usually given the initial concentrations of the reactants and so we put those in the ICE table. For the most part the reactants will be 0 if we are not given them since it is basically saying that they have not been formed yet.

Gustavo_Chavez_1K

By adding all of the partial pressure values you can get the total pressure.

Gustavo_Chavez_1K

Yeah, when you are losing reactant then the reactant's change would be negative and with that the product's change would be positive since you are gaining some. This could also be done in the reverse order so gaining reactant and losing product.

Gustavo_Chavez_1K

For the ICE method I think we generally just use it for weak bases and acids, and I guess if you are unsure on whether the base or acid is strong then it may be safe to still use the ICE method.

Gustavo_Chavez_1K

When reversing a reaction, the value of K becomes the inverse of the forward reactions K (1/K).

Gustavo_Chavez_1K

I too was confused on what Dr. Lavelle meant by "inert gas", but it basically is just another word for noble gas. These gases are usually unreactive.

Gustavo_Chavez_1K

Dr. Lavelle stated in lecture that we will almost always use Kelvin when working with temperature in equations.

Gustavo_Chavez_1K

It all just depends on the units that we are using. Each different value of R is essentially the same, they are only different because they are given in different units.

Gustavo_Chavez_1K

Kc is used when the concentrations of reactants and products are given for a solution. Kp is used when the partial pressure is given for a gas.

Gustavo_Chavez_1K

We would only use the Latin names for anions

Gustavo_Chavez_1K

There are just present in different locations. So hemoglobin is present in the blood while myoglobin is present in muscle tissue

Gustavo_Chavez_1K

To my understanding an example of a tetrahedral is a lot more common than that of square planar, but Dr. Lavelle said in lecture that we wouldn't necessarily need to know which of the two shapes it is. All we need to know is that it can be either of the two shapes.

Gustavo_Chavez_1K

Cis isomers are when two of the same ions are on the same side. This means that there are dipole moments present in the isomer. Trans isomers are when the ions are on opposite sides. So this means that the dipole moments essentially cancel each other out.

Gustavo_Chavez_1K

Yeah so the only difference is that the tetrahedral complex has four bonds so it is attached to four ligands, while the square planar has only 3 bonds and a lone pair of electrons which counts as the fourth region of electron density.

Gustavo_Chavez_1K

My TA told us that we should try and memorize the VSEPR models as it will help us out a lot when taking the final.

Gustavo_Chavez_1K

The coordinatiom number describes the number of bonds the central atom formed so it does not necessarily look at electrons. Also, in regions of density lone electron pairs are considered regions of density and this has no correlation with the coordination number.

Gustavo_Chavez_1K

En stands for Ethylenediamine and basically donates a pair of electrons to a metal.

Gustavo_Chavez_1K

When using -ate we have to first look at whether the entire compound has an overall negative or positive charge. If it has an overall negative charge then we would use -ate when naming the compound.

Gustavo_Chavez_1K

So the ligands are essentially the atoms that are attached to rhe central atom. We can calculate the coordination number by looking at the number of ligands (or atoms) that are attached to the central atom.

Gustavo_Chavez_1K

Yeah so basically a sigma bond is always present in single, double, and triple bonds.

Gustavo_Chavez_1K

If the bond order is zero then that means that the molecule is too unstable and therefore will not create a bond.

Gustavo_Chavez_1K

When trying to find hybridization you should look at the number of electron dense areas (so bonds and lone pairs). In this problem carbon has 4 single bonds meaning it has 4 electron dense areas and oxygen has 2 single bonds and 2 lone pairs meaning that it also has 4 electron dense areas. This mean...

Gustavo_Chavez_1K

Yes electron density is pretty much a section where electrons are pretty much present. So since bonds and lone pairs have electrons they would be denoted as regions of electron density. The more electrons then the higher the electron density.

Gustavo_Chavez_1K

For these questions make sure to just pay attention to what the question is specifically asking. So here it is specifically talking about P. In the diagram P is bonded to 3 O atoms and it has 1 lone pair. So since there are four regions of electron density then the hybridization is sp3.

Gustavo_Chavez_1K

So essentially Dr. Lavelle was trying to touch up on the fact that ionic bonds form between two ions of opposite charges. So instead of basically sharing electrons as in a covalent bond, ionic bonds happen when an ion essentially is taking an electron from another ion. This force causes the electron...

Gustavo_Chavez_1K

Yeah so since the G-C pair has 3 hydrogen bonds in comparison to A-T which only has 3, G-C pairs would be considered both stronger and more stable. Also, this would explain why G-C pair bonds need higher temperatures to be denatured.

Gustavo_Chavez_1K

H could never be a central atom as it only has one valence electron, meaning that it could only form one bond. Also, central atoms in Lewis structures tend to be those with the lowest ionization energy so keep that in mind when making these structures!

Gustavo_Chavez_1K

We want the formal charge of the resonance structures to be as close to 0 as possible. So the structure that provides a formal charge closest to 0 will be considered the most stable.

Gustavo_Chavez_1K

The oxidation number refers to the number of electrons gained or lost, so it could be a positive, negative, or zero. Basically it helps keep track of electrons in an atom. There a couple of different rules when determining oxidation numbers, for example, the oxidation number of an atom is zero in a ...

Gustavo_Chavez_1K

Essentially polar bonds form when there are two bonded atoms that an uneven distribution of charges due to an unequal sharing of electrons. Nonpolar bonds form when two atoms have an equal distribution of charges due to an equal sharing of electrons.

Gustavo_Chavez_1K

Yeah so although there are more electrons we must keep in mind that this means that there are also more protons. So, the more protons there are in the nucleus then the more the nucleus pulls on the electrons. This ultimately decreases the radius of the atom.

Gustavo_Chavez_1K

We can't necessarily determine an exact value for electronegativity, but what this class wants us to focus on is the period trend. So electronegativity increases when going up and to the right of the periodic table. This would make fluorine the most electronegative element on the table.

Gustavo_Chavez_1K

Yeah I agree with what mostly everyone is saying. The number of bonds has the largest effect on bond strength, followed by atom size, and the finally by the number of lone pairs.

Gustavo_Chavez_1K

I do not think that we need to know how to calculate bond length necessarily. However, we should definitely be able to differentiate bond length based on the number of bonds. The higher the bond order (single bond, double bond, triple bond), the shorter the bond length.

Gustavo_Chavez_1K

Hydrogen bonding only occurs in molecules where hydrogen is covalently bound to either nitrogen, fluorine, or oxygen. This is because these three elements are extremely electronegative and so are very attracted to hydrogen.

Gustavo_Chavez_1K

Polarity is similar to characteristics of ionic bonds in the sense that they both describe partial positive and partial negative charges. This means that electrons are shared unequally.

Gustavo_Chavez_1K

Yeah so to conserve energy, electrons will fill orbital levels that with the lowest energy levels. This is why 4s is filled before 3d.

Gustavo_Chavez_1K

Respiratory acidosis essentially is when the lungs can not remove enough of the CO2 produced by the body. The excess amount of CO2 present in the body then causes pH levels of numerous bodily fluids to decrease, leading them to become acidic.

Gustavo_Chavez_1K

Yeah so since the bond is representative of an oxoacid, determining bond length will not be useful in deducing which acid will be stronger. With oxoacid's we should pay attention to the number of oxygen atoms attached to the central atom. In regards to your question on whether HClO or HClO2 is more ...

Gustavo_Chavez_1K

I am not sure whether this is correct, but I believe that minimum uncertainty is basically the smallest value of "error" that there can be. Like lets say that the uncertainty value given for a certain measurement in a question is 15, we would use 15 to find the minimum uncertainty value. B...

Gustavo_Chavez_1K

Honestly, atomic and ionic radii are pretty similar in what they measure. The main and essentially only difference is that the ionic radius measures the distance from the nucleus to the outermost electrons in a ion while the atomic radius measures the distance from the nucleus to the normal valence ...

Gustavo_Chavez_1K

I think that the general order of the strength of bonds is: covalent, ionic, and hydrogen. What I have noticed though is that in some instances people say that ionic bonds are stronger than covalent bonds, but I think this depends on whether the bonds are intramolecular or intermolecular.

Gustavo_Chavez_1K

The closer an element is to completing their valence shell then the more electronegative they are. This is because they have a stronger tendency of attracting a bonding pair of electrons since they essentially really want to complete their shell.

Gustavo_Chavez_1K

I honestly have found conflicting answers on this question too. From what I remember learning, I think that covalent bonds are generally the strongest. But ionic bonds may be stronger depending on the maximization of the attraction between ions of opposite charges.

Gustavo_Chavez_1K

In discussion my TA lightly explained hydrogen wave functions and different atomic orbitals of the electron in a hydrogen atom at different energy levels. When explaining he talked about the different phases and even numbered them in each image of the different atomic orbitals. I'm confused on how w...

Gustavo_Chavez_1K

Black body is essentially a surface that absorbs all incident radiation that hits it and, in turn, emits black body radiation. This concept is idealized though since there isn't any surface that is completely black.

Gustavo_Chavez_1K

Honestly this is a really good question! It would make sense to just fill up an orbital before moving to the next, however electron's are all negatively charged. Since they are all negatively charged, electrons repel and want to stay far away from one another as possible. To do this, they fill up al...

Gustavo_Chavez_1K

Electron affinity basically measures the energy change when a neutral atom attracts an electron to become a negative ion. Electronegativity measures the ability of an atom to attract bonding electrons to itself. One thing to keep in mind though is that both electronegativity and electron affinity in...

Gustavo_Chavez_1K

The statement is false as an increase in intensity is not associated to an increase in the energy of a photon. By increasing intensity, the only thing changing is the number of photons of light and not the energy of each individual photon. In order to increase the energy of a photon one would have t...

Gustavo_Chavez_1K

Those are essentially all of the trends present on the periodic table. The only other ones are the atomic radius and metallic and nonmetallic character. The atomic radius is the measure of the size of an elements atoms. Metallic character refers to the level of reactivity of a metal and non metallic...

Gustavo_Chavez_1K

Protons and electrons do not have the same mass. Both protons and neutrons have a much larger mass than electrons. However, protons and neutrons have essentially the same mass. Neutrons are only a little larger in mass than protons, but nothing too major.

Gustavo_Chavez_1K

The threshold function and work function are basically the samething. Professor Lavelle was using them almost interchangebly in lecture and I remember writing in my notes that in this scenario they essentially both signify the lowest amount of kinetic energy required to eject an electron.

Gustavo_Chavez_1K

Exactly! So the experiment was basically just them changing the intensity of the light, so making it brighter. This is why they noticed that the electrons were not being ejected. However, once they changed the type of light, so the frequency, that is when the electron were ejected.

Gustavo_Chavez_1K

I too am having trouble staying on top of chem. It is incredibly easy to get behind especially since lectures are recorded and the homework is the sundays. But I study by taking notes during lecture and highliting key concepts and terms. I also make sure to look into khan academy videos on math conc...

Gustavo_Chavez_1K

I too am having trouble staying on top of chem. It is incredibly easy to get behind especially since lectures are recorded and the homework is the sundays. But I study by taking notes during lecture and highliting key concepts and terms. I also make sure to look into khan academy videos on math conc...

Gustavo_Chavez_1K

In lecture Lavelle stated that we need to get rid of fractions as stochiometric coefficients should be whole numbers. So I assume that in the homework, exams, and in general we should make it a habit to convert fractions in chemical equations to whole numbers.

Gustavo_Chavez_1K

Yeah I completely understand too as I have also been confused on the theoretical and actual yield. So I did some minor research and the theoretical yield is essential the amount of product made if there were no errors made. This is basically impossible though due to side reactions and other things t...

Gustavo_Chavez_1K

Yes, the empirical and molecular formula can be the same. It essentially depends on the ratio we calculate when determining the empirical formula. For example, if the ratio ends up being 1:1:1 then the empirical formula and the molecular formula will be the same. However, lets say that the empirical...

Gustavo_Chavez_1K

I feel as if though it is highly unlikely that we will need to memorize the periodic table, but we will need to understand how to read a periodic table and acknowledge what the different parts of the periodic table (such as the atomic name, atomic number, atomic symbol, and atomic mass) mean.

Gustavo_Chavez_1K

What I recommend is counting how many of each element there is in total on the reactant side and then counting the total of the same element on the product side and writing that down. By knowing how much of each element there is on each side, one can then take note on which side they will have to ma...

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