CHEMISTRY COMMUNITY

SMIYAZAKI_1B

As may says, it does not matter which order you should do to calculate the order of the reaction; however, you probably should place the half-reaction with higher values to be on the top to make sure that you are given with number bigger than 1 which is easier to deal with.

SMIYAZAKI_1B

Yes, the final would be timed from 11:15 AM with three hours and thirty minutes in total.

SMIYAZAKI_1B

According to Dr. Lavelle's email today, he stated that the submission of the final would be on CCLE. Though we are still unsure of how the system exactly works, he hopefully clears it up soon.

SMIYAZAKI_1B

The rate constant of the equation can easily alter if the reaction adds catalyst or temperature is changed. With the changes made in the system, it allows the reaction to change the rate of the reaction taking place per reaction.

SMIYAZAKI_1B

The rate constant of the equation can alter in two ways: Changing temperature and addition of the catalyst. This can be considered as mixing salt into the water. If you add heat into the water, the molecules will vibrate even more which causes it to dissolve even more, and if you add some sort of pr...

SMIYAZAKI_1B

It is better to keep it in Kelvin just because of the unit of the gas constant, R, has Temperature in Kelvin. In order to cancel out the units, you really have to make sure that units match and if you really really need Celcius, make sure to change the unit after figuring the Kelvin.

SMIYAZAKI_1B

The wording is definitely a little difficult to understand but I am also assuming that you are asking us for which redox hzlf equation to switch the product and reactant sides. I would say that generally, you would want to have the cell potential to be positive in order to allow the system to have s...

SMIYAZAKI_1B

On the last bit of this note, I wrote “magnitude of (delta)S depends on T at which heat is transferred.” What does this mean?

SMIYAZAKI_1B

When it comes to third law of thermodynamics, by taking a limit, does that mean that as the temperature of the system becomes 0K, entropy becomes 0? So for this equation, because it is absolute zero, there would be no more movement of the molecules which means there would be no possible positions?

SMIYAZAKI_1B

What is the difference between reversible and irreversible pathway? Like in the equation, we use q(REV). Is it just stating that reaction is reversible or not?

SMIYAZAKI_1B

Can someone describe entropy in a easy way for me? It gets a little confusing.

SMIYAZAKI_1B

When solving the bond enthalpies, does the sigma bond break or the pi bond in double bonds? I know Dr. Lavalle talked about it but I wrote both so it’s confusing.

SMIYAZAKI_1B

I personally also look through the lecture notes and examples that we have done during class. With some of the math problems like Ka calculation and so on, you would like to try doing some practice problems from the book he assigned; however, majority, as the person before stated, I tend to study of...

SMIYAZAKI_1B

Amphoteric- molecule being able to react as both acid and base in different cases
Amphiprotic- Can both accept and donate H+.

SMIYAZAKI_1B

Myoglobin is important in organisms because it can carry oxygen and store them. When in need of the oxygen by the muscle, (to create energy) these stored oxygen will be used to create energy to fuel the muscles.

SMIYAZAKI_1B

I felt like he really did integrate both the first and second quarter together in a way that it sometimes caught me off guard. It was kinda difficult.

SMIYAZAKI_1B

Cobalt is an important in biological systems because it can create myelin sheaths in nervous system and also it is a part to produce red blood cells. It is also a part of vitamin B12 which is important for metabolism of folic acids and fatty acids.

SMIYAZAKI_1B

Hemoglobin’s purpose is to carry important biological molecules like oxygen and carbon dioxide. Myoglobin’s purpose is to store oxygen within itself. Myoglobin’s stored oxygen are often times used by the muscles when there is a huge need of the oxygen upon physical activities to create energy.

SMIYAZAKI_1B

A Bronsted acid is a proton/H+ donor and a Lewis acid is an electron acceptor, while the each bronsted and Lewis base has complementary characteristic.

SMIYAZAKI_1B

If I am not wrong, within water, acids releases hydrogen atoms. Therefore, as a result, the hydrochloric acid will split into hydrogen and chlorine atom which causes the diagram to be the most accurate picture.

SMIYAZAKI_1B

I am unsure of why the substitution reaction does occur; however, the bond between the acid and base breaks apart and the acid or base takes the place of the other by forming a coordination bond between the reactive centre and the new molecule. When I do my research, I have read that this process is...

SMIYAZAKI_1B

If I have not read your question wrong, the non polar molecules can form as long as the dipole forces can cancel out each other. Therefore, if you can somehow cancel out the force, you can definitely make the molecule non pole and not symmetrical.

SMIYAZAKI_1B

I also do agree with the fact that order does not matter, however, you just have to make sure that number goes along with the correct orbital that is correlated. If there is three p orbitals used for hybridization, you have to put 3 after p but you can never switch the values around.

SMIYAZAKI_1B

It is hard to determine the exact angle of the seesaw shape because every element differs in size and as a result, we can never determine the exact angles unless you remember the bond angles. However, in general you can consider each angles of the trigonal bipyramidal decreased as seesaw’s bond angle.

SMIYAZAKI_1B

If one bond is broken from the molecule, the energy required to break all of the bonds in the molecule decreases. Therefore, the melting point decreases as a whole.

SMIYAZAKI_1B

Cis and trans refers to the difference in the orientation of the elements around the central atom. If the elements are in the same side, it’s CIF and opposites of each other is trans. This is only applicable to certain chemicals though and this difference makes the chemical properties a lot different.

SMIYAZAKI_1B

Lone pairs on the central atom has higher electron repulsion energy present in comparison to the bonds. Therefore, you will see the bonds being pushed downwards and closer to each other because repulsión created by lone pairs will cause the bond angles to decrease.

SMIYAZAKI_1B

Commonly, hydrogen bonding is polar due to its nature of bonding only with N,O, and F. Since hydrogen isn’t high on electronegativity, the difference will always be larger towards the other element.

SMIYAZAKI_1B

Like the other student said, the trend is true for most of the elements except for Boron and Oxygen. Boron actually does have a lower IE in comparison to Beryllium and it is for a similar reason of Oxygen.

SMIYAZAKI_1B

There are a lot of suggestions that are made and one of them suggests about the Kg being able to accommodate ampere and volt. Some do say that it is rather because of political controversies but I do believe that it is because it was more used unit over grams.

SMIYAZAKI_1B

They will all have dipole moments; however, the degree of which electrons are pulled towards one certain direction is different because chlorine can attract electrons more than hydrogen.

SMIYAZAKI_1B

You can consider that bond is polar if there are a difference in electronegativity. If the electronegativity is different, it means that there are difference in how much the nucleus will pull the shared electron towards it.

SMIYAZAKI_1B

I would agree with the other students and say that it would definitely help you to understand all of the shape names and also try to remember the bond angles. At least on the midterm, we did have a molecule with more than 8 valence electrons in the valence shell.

SMIYAZAKI_1B

Temporary dipole moment is created because the electrons are in constant movement and it spontaneously comes close to proximity of the nucleus. Since it is spontaneous and not constant, it is temporary.

SMIYAZAKI_1B

As the response before me says, electronegativity and dipole-dipole attraction are not exactly something similar. Since electronegativity is a measurement to see how much each element will likely attract the electrons within the bond to form an octet valence shell and dipole- dipole attraction is a ...

SMIYAZAKI_1B

You can determine that molecules have a dipole moment by looking at the difference in values for electronegativity. More the difference, more likely that molecule has dipole moment. (Since dipole moment is all about which element will pull the electron more within the bond)

SMIYAZAKI_1B

Most of the times, the elements are chosen so that we can easily understand just from the periodic trends; however, if it is difficult to get the value, he will provide you with the numbers.

SMIYAZAKI_1B

An atom is more electronegative when they are close to being octet. As many do say, it is a measurement of how an element may pull the electrons towards itself and it can be used to see whether the bond is ionic or covalent bond.

SMIYAZAKI_1B

Electronegativity is a characteristic of elements that defines how often these elements will try to gain more electrons from the bonding partner. (Whether it is covalent or ionic bond) It is important to also note that electronegativity increases as you go across and upwards. Consider it as like if ...

SMIYAZAKI_1B

As many of the others say, you just need to know the basic trends for electronegativity and it would probably be helpful to understand the boundary of which two elements would form covalent and ionic bond.

SMIYAZAKI_1B

Even though it is not shown, Phosphorus is in the 3rd shell which also has 3d10 as a part of it. Therefore, because Phosphorus's valence electrons end at 3p shell, we can also place electrons into the 3d shell which allows phosphorus to carry ten more electrons in its outer shell.

SMIYAZAKI_1B

In general senses, those elements will be an exception to the octet rules. Of course it does not mean that they HAVE to always, but in most of the cases, it is much more stabilized if they defy the octet rule due to formal charges being close to 0. If you recall like HClO4, you know that formal char...

SMIYAZAKI_1B

When it comes to resonance,think of it like bunch of blocks. You can place the block in the shape of T, but those blocks can be rearranged, right? As long as the rules are met and it is formatted correctly, they can swap around because it still is a same structure.

SMIYAZAKI_1B

When it comes to expanding the shells, it means that the electrons that should've gone to the new shell instead goes to the orbital's d-shell. For example, if the element is 3p5 and they have to accommodate 3 more electrons, they would bring them to 3d shell.

SMIYAZAKI_1B

It is because of the electron affinity difference between oxygen and sulfur. Between sulfur and oxygen, oxygen has more stable structure when they have that charge in comparison to sulfur. Therefore, since compounds look for then most stable structure in most of the cases, oxygen should have the for...

SMIYAZAKI_1B

The most stable structure would be the best structure you want to use in any sort of questions as others do say. But if the question asks for resonance structures, of course put all of the possible structures and make sure to define which one is most stable and why.

SMIYAZAKI_1B

As the first person mentioned, the Lewis Structure for resonance does not always have a octet rule. Of course, as we always say, Hydrogen, Helium, lithium, and Beryllium does not have octet rule but it has duet rule. Other certain structures does have a different types of rules as well such that som...

SMIYAZAKI_1B

As others do say, yes you draw a double sided arrows between the resonance structures. You still draw the resonance structures like the way we have been and you just add the double sided arrows.

SMIYAZAKI_1B

In general, resonance structures hold the same amount of energy; however, of course when the bond changes from single bond to double bond, then the bond strength changes.

SMIYAZAKI_1B

According to the Hund's rule, it is said that we have to fill one into each sub shell of the orbital before doubling any of the sub shell with electrons. Therefore, in each of the sub shells, you cannot have an opposite spin of the electrons until each sub shell are filled with parallel spinning ele...

SMIYAZAKI_1B

To add onto it, they are exceptions because when you consider electron configuration and energy levels, because 3d will end up being in the inner orbital of the electron orbitals, you would want to stabilize that one before stabilizing the others. Therefore, for copper and chromium, the one electron...

SMIYAZAKI_1B

In addition, when the valence electrons of these elements are used for chemical reactions...
Fe 1s2 2s2 2p6 3s2 3p6 3d6 4s2
Fe3+ 1s2 2s2 2p6 3s2 3p6 3d5
The electrons from 4s orbitals are used first.

SMIYAZAKI_1B

Okay so this might sound weird, but when the electrons are not filled into these two orbitals, 3d shell actually does have a higher energy. Therefore, the electrons will fill up 4s orbitals, which are much lower in its energy. However, once the electrons have filled for both shells, the. 4s sub-shel...

SMIYAZAKI_1B

Surely, the equation is derived from the equation but you have to also consider that because electron is not electromagnetic radiation, (it has wavelike movement and all but it isn't the radiation) you cannot apply those equations to De Broglie's equations.

SMIYAZAKI_1B

If you ever forget, you can always think about the exponent rules from Algebra. As long as the base number or variables are the same and they are dividing each other, (in this case, the variable is s) you can subtract the exponent of the numerator from the denominator. Since any number to 0 is 1 acc...

SMIYAZAKI_1B

He pretty much said that we were allowed to do both fundamental principles or quantum world problems. Probably fundamentals just because we just had a test and he wanted us to practice and he also wants us to try new set. of problems.

SMIYAZAKI_1B

So when it comes to dilutions, I understand how to calculate the molarity and concentration of the molecule or element; however, how can you solve for a volume of the water necessarily to dilute the solution to a given molarity with given volume? I feel like I have explained myself really badly so.....

SMIYAZAKI_1B

So in class today, we discussed about De Broglie's equation, but what is momentum? I understand that it has the unit and variable for itself but can anyone explain what does momentum really is?

SMIYAZAKI_1B

I guess to explain that, sun is not actually a typical combustion. It burns hydrogen molecules to create helium as a product alongside of heat which is what is considered as a "burning" portion of the sun. The heat and the light comes from nuclear fusion where the helium is forcefully crea...

SMIYAZAKI_1B

I am assuming that you are asking if you can just leave the Volume of the one as milliliters? If that's the case, yes you can. Think of the units that are canceling out. If M1 and M2 has the same unit, it cancels out together. As long as you remind yourself that you are using the same units for M1 a...

SMIYAZAKI_1B

Do you know if the problems will specifically tell us how many significant figures to use? Okay so when it comes to sig figs, it isn't about the problem telling you which places to round up to, but rather it is about how many digits are present in the values provided. For example, had said that pro...

SMIYAZAKI_1B

Question regarding Fundamental E 15: The question on the textbook states... The molar mass of the metal hydroxide M(OH)2 is 74.10 g/mol. What is the molar mass of the sulfide of this metal? I am very unsure of what the textbook is trying to state. Does the "metal" part refer to the sulfide...

SMIYAZAKI_1B

I used to be on Cross Country team back in my high school years, so I will tell you what I used to do back in my high school days. For me, the best way to calm myself down is to really think about all of the practice problems I have done and all of the preparations I have done. I tend to think, &quo...

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