CHEMISTRY COMMUNITY

Irma Ramos 2I

In order to check me answers for this one, I just thought of the ones that included final minus initial.

Irma Ramos 2I

An adiabatic process means that heat isn't being transferred, so q equals 0. The internal energy in this case would equal work.

Irma Ramos 2I

I think it would be important to know the difference between a catalyst and an intermediate and how to tell that a catalyst needs to start in the reactants and end up in the products.

Irma Ramos 2I

Will there ever be a situation where there isn't an intermediate and we're still asked to find one? Do we just come to the conclusion that there aren't any?

Irma Ramos 2I

When using the Arrhenius Equation, are we always going to use it in the form k=... or are we going to have to know how to re-arrange it and solve?

Irma Ramos 2I

Why do we do the pre-equilibrium approach in respect to the excess reactant when there are two reactants?

Irma Ramos 2I

Can someone explain why the slope is negative for a zero order reaction when we are plotting [A] vs. time?

Irma Ramos 2I

Yes, the slope of a second order graph is always positive because after integration of the rate law, k ends up being positive. If k were to come out to be negative, you know it is a first order reaction.

Irma Ramos 2I

Is it safe to say that the slope for a first order graph is always negative?

Irma Ramos 2I

Why is it that when comparing different reaction rates, the reaction rate only depends on the reactants? Why do we just compare the initial rates rather than the rates at the end of the reaction as well?

Irma Ramos 2I

What exactly does it mean when it says that the rate constant K depends on temperature and activation energy??

Irma Ramos 2I

The signs depends on whether or not the rate is for the products or reactants. For products, the rate is positive, and for reactants, the rate is negative.

Irma Ramos 2I

When remembering which one is the reducing agent and which one is the oxidizing agent, it's safe to say that the oxidizing agent is one being reduced and the reducing agent is the one being oxidized. This may be confusing at first, but hope it helps.

Irma Ramos 2I

How does one know when to add H2O, H+ or OH- when balancing redox reactions? and on what side of the reaction to add them to?

Irma Ramos 2I

Are the ways in which one balances a redox reaction in acidic conditions different from the way one balances one in a basic condition? If so, how?

Irma Ramos 2I

A salt bridge is needed because it allows for the ion transfer, thus keeping the solutions neutral.

Irma Ramos 2I

As mentioned above, one needs to pay attention to see if the entropy that one is talking about is for the system or the total entropy because whether or not the entropy can determine the spontaneity is based on whether it's the total or for the system.

Irma Ramos 2I

Would the above situations be the only ones where this equation is used?

Irma Ramos 2I

Would there ever be a time when we are asked to calculate K but not given delta H? If so, then how would we solve for K?

Irma Ramos 2I

I'm a little confused as to when we use the Gibbs free energy equation that includes pressure? Are we going to be told to use it in a question or do we have to know when to use it by our own knowledge?

Irma Ramos 2I

It refers to the free energy which must be negative in oder to be favored and because of this the entropy is positive and the process is spontaneous.

Irma Ramos 2I

Yes, it is a state function like enthalpy because it isn't dependent on the path taken to obtain the state it is in.

Irma Ramos 2I

In lecture, it was mentioned how entropy increases as a solid melts or turns into a liquid, and entropy decreases when a liquid goes to a solid. This would support the above post about the relationship between temperature change and entropy.

Irma Ramos 2I

What exactly does it mean to say that a reversible process does more work or the max work??

Irma Ramos 2I

Based on the above responses, is it safe to say that there is only work done when there is a change in volume???

Irma Ramos 2I

Yes, as mentioned above depending on the question and what is being asked we would be able to differentiate when to use either or value for R. It is important to remember the units because this will help us distinguish which one to use.

Irma Ramos 2I

An isolated system doesn't exchange anything with its surroundings, and a closed system can exchange energy with its surroundings but not matter.

An example of a closed system is a sealed beaker of water, and an example of an isolated system is the combustion of glucose in a bomb calorimeter.

Irma Ramos 2I

An intensive property doesn't depend on the amount of substance where as an extensive property does depend on the amount of substance so yes an intensive property would be more useful to use because it won't change based on the amount of substance.

Irma Ramos 2I

Is it true that in irreversible processes, the pressure can be considered constant, and in a reversible process, the pressure is constantly changing so the pressure isn't constant??

Irma Ramos 2I

As mentioned above, because state properties don't rely on the path taken to get to their state they can be added and subtracted. They are independent in other words so adding and subtracting them is allowed.

Irma Ramos 2I

How do we know whether or not something is an acid or base from drawing the Lewis structure??

Irma Ramos 2I

Do we need to be able to name the acids as well as know their molecular formula for the final??

Irma Ramos 2I

How can one find if a molecule is polar or nonpolar when the Lewis structure isn't given? Do we need to draw it out to figure this out??

Irma Ramos 2I

In order to find if ligand is bi-, tri-, etc dentate, do we need to draw out the Lewis structures or is there an easier way to do this??

Irma Ramos 2I

Will there ever be situations in which Q is equal to K and if this is the case, which direction will the reaction proceed??

Irma Ramos 2I

With this, does that mean we completely disregard the solids and liquids when calculating the K constant? The gaseous reactants and products are the only ones used??

Irma Ramos 2I

Can someone further explain the relationship between ligands and coordination spheres and how they relate to the coordination number??

Irma Ramos 2I

sigma bonds allow bound atoms to rotate which allows them to have electron density with cylindrical symmetry around the internuclear axis, while pi bonds don't allow for rotation of bound atoms which explains the electron density on each side of internuclear axis

Irma Ramos 2I

Do we always have to multiply by 2 in order to find the delta v for these problems??

Irma Ramos 2I

How do we find the mass of atom given the molar mass of the element in order to use the de broglie equation??

Irma Ramos 2I

Is there any way to tell if a bond is ionic or covalent without having to calculate the electronegativity difference?

Irma Ramos 2I

Given the information above, why is it that expanded octet structures have lower energy than regular octet structures? Is it because of it having a d-orbital?

Irma Ramos 2I

Other than the removing and addition of electrons, are there any other differences between anions and cations?

Irma Ramos 2I

Lewis structures with resonance, for example nitrate, when asked to draw the lewis structure would we be able to draw any of the three possible structures that we went over in class and still have the correct answer or is there one preferred over the others?

Irma Ramos 2I

During lecture today, it was mentioned that the rows of the periodic table correspond to quantum numbers. What exactly does this mean?

Thanks!

Irma Ramos 2I

During lecture today, it was mentioned that the rows of the periodic table correspond to quantum numbers. What exactly does this mean?

Thanks!

Irma Ramos 2I

I'm not sure if I'm wording this correctly, but when writing the electron configurations, do we have to include the x, y, and z for like the p-orbital or can we simply just write it all as p?

Irma Ramos 2I

Is it safe to say that electromagnetic radiation and wavelength are inversely proportional, while frequency and electromagnetic radiation are directly related, based on the responses above?

Irma Ramos 2I

Can someone please help with this question:
A lamp rated at 32W emits violet light of wavelength 420 nm. How many photons of violet light can the lamp generate in 2.0 s? How many moles of photons are emitted in that time interval?

Thanks!

Irma Ramos 2I

Yes, I agree. It's always good to save the rounding and finding the sig figs for the end. Doing it like this allows for the answer to be more accurate.

Irma Ramos 2I

Honestly, when balancing equations I usually go with the first one that comes in the order of the equation and from there I balance the rest. I might need to go back and fix ones that I already balanced, but this usually works.

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