CHEMISTRY COMMUNITY

Anthony_Sandoval_1D

It really depends on the book and class but in our case, they mean the same thing. I would just use Ea though since that is what is primarily used in lecture.

Anthony_Sandoval_1D

As a previous person said, a catalyst does not affect enthalpy. This is because enthalpy is a state function and is not dependent on the path taken. A catalyst only changes the amount of energy needed to reach the location and but does not affect the final or initial value.

Anthony_Sandoval_1D

A catalyst will be present at the beginning of a reaction and at the end of the reaction. An intermediate on the other hand is present at the beginning but is eventually consumed by the end of the reaction. So yes, a catalyst will appear on the left side towards the beginning but shifts to the right...

Anthony_Sandoval_1D

Enzymes act as a catalyst by lowering the activation energy of a reaction. This allows the reaction to take place at a faster rate.

Anthony_Sandoval_1D

Basically, a catalyst is not consumed in the reaction whereas intermediates will be present at the beginning of the reaction but eventually be consumed.

Anthony_Sandoval_1D

Yea some questions take into consideration the states of matter. I would try to always include them just to be on the safe side.

Anthony_Sandoval_1D

You would find the number of moles by looking at the number of electrons transferred. This is done after balancing the reaction.

Anthony_Sandoval_1D

When water is added to the solution it shouldn't affect the cell potential. This is because the proportion of reactants to products should stay the same.

Anthony_Sandoval_1D

E naught will typically be equal to zero in a concentration cell. This is also the case in an oxidation and reduction reaction end up adding up to zero.

Anthony_Sandoval_1D

The symbol means that they are in standard conditions so the answer would be yes. They are both the same.

Anthony_Sandoval_1D

n is the number of moles of electrons that are being transferred. You find n after balancing the reaction and splitting it into half-reactions.

Anthony_Sandoval_1D

Although it would be efficient to memorize all of the oxidation numbers, we don't have to. I would just try to remember the more important ones or the ones that we tend to use more in class.

Anthony_Sandoval_1D

You would usually be given the phases at the beginning of a problem and if not then I personally just memorize them. For example, I know OH is aqueous.

Anthony_Sandoval_1D

Yes, the oxidizing agent is the molecule that has been reduced while the reducing agent is the one being oxidized.

Anthony_Sandoval_1D

As previous comments have stated, yes you would use the list of ions to find the reduction potential. The highest reduction potential should be the oxidizing agent.

Anthony_Sandoval_1D

No, they are not the same. Both contribute to a change in energy and give you the internal energy (U). However, work is, as someone earlier mentioned, force over distance whereas heat is the energy transferred over after an increase or decrease in temperature.

Anthony_Sandoval_1D

An open system allows for the exchange of energy and matter with the surroundings. A closed system allows for energy to be exchanged with the surroundings whereas an isolated system does not allow for any exchange to occur with the surroundings.

Anthony_Sandoval_1D

Yea, a thermal mug would be an excellent example of an isolated system as nothing comes in or out! A thermal mug without a lid would be an open system.

Anthony_Sandoval_1D

That's a big time lapse but ima assume you're talking about the different systems. An open system is similar to a cup of water with nothing to cover the top with. A closed system would be like putting a lid on top of a mug with coffee. An isolated system is like a bomb calorimeter. Basically, nothin...

Anthony_Sandoval_1D

Degeneracy is the number of equal energy states. In thermodynamics, the more degeneracy increases, the more entropy there is.

Anthony_Sandoval_1D

d is for derivatives but I would just focus more so on when the equations are used.

Anthony_Sandoval_1D

Standard molar entropies increase as the complexity of substance increases because more positions become possible to occupy allowing for an increase in entropy to take place.

Anthony_Sandoval_1D

At lower atm there is higher entropy because at lower pressures there is greater volume. More volume means more entropy.

Anthony_Sandoval_1D

Going from gas to a liquid is an increase in order thus a decrease in entropy. However, the entropy of the surroundings increases.

Anthony_Sandoval_1D

It depends on the problem. You have to look at the constants but the majority of problems use the constant 8.314.

Anthony_Sandoval_1D

You choose the R-value that matches your units which seems to usually be atm. It all depends on what is given to you in the problem.

Anthony_Sandoval_1D

An open system has constant pressure because the moment pressure comes out, more pressure comes in to take the place. Yes, the universe is that big.

Anthony_Sandoval_1D

When there is no chance in Temp then the value of q would be 0.

Anthony_Sandoval_1D

Thermal energy is the energy inside the system whereas heat is the energy that is capable of going in and out of the system. It helps to think of phase changes and what not.

Anthony_Sandoval_1D

Like earlier replies have mentioned, the heat is most likely going to breaking bonds instead of adding on to the temperature.

Anthony_Sandoval_1D

Steam causes burns because when it converts into liquid upon contact with the skin because the water is going from vapor to liquid releasing heat and energy that has been built up.

Anthony_Sandoval_1D

Delta u is the total amount of energy whereas delta h refers specifically to the amount of work.

Anthony_Sandoval_1D

This is possible however it depends on the information given in the problem. I believe you would need to know the enthalpy for formation values.

Anthony_Sandoval_1D

Basically, it's saying that enthalpy is a state function and therefore is additive.

Anthony_Sandoval_1D

No conversion would be needed as the same amount of distance exists between each unit for Kelvin and Celsius.

Anthony_Sandoval_1D

I believe, as also previously mentioned by others, that once the heat has broken hydrogen bonds it will go into raising the temperature of the sample.

Anthony_Sandoval_1D

Breaking bonds requires energy because they must overcome the potential energy holding them together. As someone previously said, the formation of bonds is exothermic and releases energy because of the decrease in potential energy.

Anthony_Sandoval_1D

I think this is because the steam particles have already come into contact with the air losing some of its temperatures. By the time the steam has come in contact with your skin, it has probably lost a considerable amount of its temperature to the environment.

Anthony_Sandoval_1D

The terms are pretty much interchangeable.

Anthony_Sandoval_1D

The temperature stays constant because the heat goes towards breaking the hydrogen bonds instead of going towards temperature.

Anthony_Sandoval_1D

A change in pressure through inert gases will not shift the reactions in either one direction as these do not change the volume.

Anthony_Sandoval_1D

You would need to determine whether the reaction is endothermic or exothermic which is given by looking at the value of delta H.

Anthony_Sandoval_1D

You would test both of the values out and the majority of the time only one will work.

Anthony_Sandoval_1D

The only factor that could lead to a change in K is temperature.

Anthony_Sandoval_1D

For this class specifically, I would recommend using the ICE box regardless of the strength of the acid or base.

Anthony_Sandoval_1D

For this class, I think we will most likely be using atm and bars.

Anthony_Sandoval_1D

Adding a constant makes the equations equal to one another. The absence of a constant would mean the equations are instead proportional.

Anthony_Sandoval_1D

It is in my opinion that we will be using atm in this specific class.

Anthony_Sandoval_1D

In this situation, you would be using kelvin.

Anthony_Sandoval_1D

Kc is used for concentration where Kp is used specifically for partial pressure.

Anthony_Sandoval_1D

Through the use of a Lewis Structure you are able to see that a tetrahedral complex has four atoms bonded to it without any electron pairs. On the other hand, a square planar complex has four atoms bonded to it and 2 electron pairs.

Anthony_Sandoval_1D

HF is not a strong acid due to the high electronegativity of F and because of its extremely small atomic radius. The small atomic radius of F means it has a very short and consequently strong bond making it very difficult to break when dissolved in water.

Anthony_Sandoval_1D

An an earlier comment mentioned, what helps me is thinking that a Bronsted Base borrows a proton whereas a Bronsted Acids donates protons. With that being said, the opposite can be said where a Lewis acid can be said to accept electrons whereas a Lewis Base donates electrons.

Anthony_Sandoval_1D

Due to water being amphoteric, it can act as an acid or base depending on the context.

Anthony_Sandoval_1D

I believe it is easier to just memorize the list of strong acids and bases then use the process of elimination.

Anthony_Sandoval_1D

Yes, there could be polar bonds and a non-polar structure canceling the polarity.

Anthony_Sandoval_1D

A triple bond has 1 sigma bond and 2 pi bonds but otherwise the order does not matter.

Anthony_Sandoval_1D

If bond order is zero then this means the molecule is too unstable. This means the molecule will cease to exist.

Anthony_Sandoval_1D

Lone pair does not mean a molecule is automatically polar. As others have said above, if an atom is symmetrical the usually this plays a bigger role in its polarity.

Anthony_Sandoval_1D

Ligands are atoms which are attached to the central atom or cation. Coordination number is calculated by counting the number of ligands attached the central atom.

Anthony_Sandoval_1D

The bent in H2O is caused by the two lone pairs. The lone pairs repel hydrogen leading to the bent shape of H2O.

Anthony_Sandoval_1D

Lone pairs are important in determining the bond shape. The reason being that they are more repulsive than bond pairs and consequently affect molecule shape.

Anthony_Sandoval_1D

No dipole charges are present in non-polar molecules. An example would be CO2 since there is no dipole charge present.

Anthony_Sandoval_1D

Bonds don't affect the shape of the molecule. However, as the person above mentioned, a single bond is the longest length wise.

Anthony_Sandoval_1D

As the last two mentioned, I would try to remember patterns for the final.

Anthony_Sandoval_1D

A stronger intermolecular force leads to a higher melting point.

Anthony_Sandoval_1D

Lewis acids accept electrons whereas lewis base donates electrons.

Anthony_Sandoval_1D

Hydrogen bonds are a type of dipole-dipole interaction so yes.

Anthony_Sandoval_1D

Dipole is basically when one atom is more electronegative than another. This causes that atom to have a strong electron pull which beings them closer. This causes one atom to be partially positive while the other partially negative.

Anthony_Sandoval_1D

To answer your question, Yes. London dispersion is occurring in all molecule interactions.

Anthony_Sandoval_1D

F, O, and N are small and are electronegative whereas H is positive.

Anthony_Sandoval_1D

More negativity in an Ion means a larger radius. On the other hand, positivity causes an Ion to have a smaller radius.

Anthony_Sandoval_1D

Double bonds are shorter because more bonding means a stronger attraction. This causes the atoms to be pulled closer to one another creating a shorter distance.

Anthony_Sandoval_1D

LDF is also affected by the distance of molecules. Larger distance means weaker forces which also means more polarity.

Anthony_Sandoval_1D

As others have said, I believe the name will be provided to us.

Anthony_Sandoval_1D

I believe it was mentioned in lecture but this is because they are exceptions to the octet rule.

Anthony_Sandoval_1D

As was said earlier, I think it's only necessary to remember that bond length is in the order of triple, double, and single with triple being the shortest and single being the longest.

Anthony_Sandoval_1D

Double bonds have stronger force of attraction due to having more electrons. This causes atoms to be drawn tighter to each other and thus creating a shorter bond.

Anthony_Sandoval_1D

After calculating the electronegativity, if it is above the value of 2 then it is a covalent bond however if it is below the value of 1.5 then it will be an ionic bond.

Anthony_Sandoval_1D

I would say it depends on the information given to you in the problem. Generally E=pc is used when you are given mass or velocity. E=hv is used when you are given frequency or wavelength.

Anthony_Sandoval_1D

A photon with less energy than the work function will not be able to eject electrons. This is only possible when the photon has at least as much energy as the work function.

Anthony_Sandoval_1D

This basically means that there are 5 orbitals in the d-subshell. Additionally, this means that it only holds a maximum of 2 electrons as an orbital can only have 2 electrons.

Anthony_Sandoval_1D

I would just try to remember that as you move towards the bottom left of the periodic table it increases while going to the top right is decreasing.

Anthony_Sandoval_1D

I pretty much just memorized them by using flashcards. If that isn't your style maybe try imagining the trends as waves that lead to different islands. Maybe associating it with an image like this will make it easier to recall.

Anthony_Sandoval_1D

Negatively charged ion have a larger radius than positively charged ions.

Anthony_Sandoval_1D

The only exception is the noble gases.

Anthony_Sandoval_1D

Another trend is the atomic radius which increases as you go down the group and decrease from left to right.

Anthony_Sandoval_1D

I believe knowing that electronegativity increases from left to right and decreases as you move down is enough.

Anthony_Sandoval_1D

I would look over the outlines sent to us and try to focus on the fundamentals.

Anthony_Sandoval_1D

A studying routine that has definitely worked for me is going through each of the lectures individuals and completing as many practice problems as I can.

Anthony_Sandoval_1D

The boiling point is higher the stronger the intermolecular force is.

Anthony_Sandoval_1D

I believe having a general idea of what the spectrum looks like should suffice so I would not worry too much about memorizing the smaller details.

Anthony_Sandoval_1D

When an ionic bond occurs, an electron is transferred from one atom to another. In other words, one atom gains an electron while the other loses the electron.

Anthony_Sandoval_1D

When an electron is ejected this means that it is entering a lower level of energy. When an electron is excited it is entering a higher level of energy.

Anthony_Sandoval_1D

Quantum is at the subatomic level whereas a photon is the smallest particle of light.

Anthony_Sandoval_1D

A photon is a particle that carries energy.

Anthony_Sandoval_1D

You do not need to memorize the periodic table but if you still would like to make attempt at it I would recommend getting flashcards and writing the chemical abbreviation with the full name on the other. Testing yourself at the end of every week will ensure that you eventually remember it.

Anthony_Sandoval_1D

I was having the same problem until I made sure I was typing in capital letters. Maybe this will solve your problem?

Anthony_Sandoval_1D

A free trial is available for two weeks. I received an email from the UCLA store a day prior to my access code arriving so I would be on the lookout for that.

Anthony_Sandoval_1D

The number with the least amount of figures determines the sig figs.

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