What the title says. Ask for help with your homework if you have problems and help others if you can.

*Jeannie, would you mind changing the title to include Helping Hand? I'm trying to categorize it to make it easier between help topics and other kinds of topics.

Personally, I liked Homework Hotline better as a title, but meh...

So anyways!

I'm back again with mah Chemistry! XD

Anyone here can explain to me the Quantum-Mechanical Model of the atom?

Or at the very least, electron configuration? Anyone?

What about electron configuration? Like, 1s1, 1s2, 1s2 2s1, etc? :/ Or... what is it exactly about electron confuguration you're not getting?

This is so Term 1. I need to brush up on my basics if I need to help with that...

Like this stuff:

What is the electron configuration for the element Niobium? (41)

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d3

I have no clue what that is supposed to mean. -_-

Electron configuration has to do with the electron shells.

Electron shells surround the nucleus.

In the example you provided the first S shell was filled with two electrons, the second S shell was filled with two electrons, the second P shell was filled with six electrons, the third S shell was filled with two electrons, the third P shell was filled with six electrons, the forth S shell was filled with two electrons, the third D shell was filled with ten electrons, the forth P shell was filled with six electrons, the fifth S shell was filled with two electrons, and the forth D shell contained only three electrons. It's this shell that would react with other elements and bond. Make sense?

HELP.

I don't understand this whole "predicting" thing with the electrochemical series. My notes given to me by the teacher say that for a reaction to happen there must a) be an oxidant and reductant present AND b) the oxidant must be stronger than the conjugate oxidant of the reductant. (ie. the species on the left hand side of the electrochemical series must be higher up than the species on the right hand side.)

And... I'm totally lost. Can someone explain this, please? D: I'm seriously missing something here. -_-;

Sorry, wish I could help but I have no clue what you're talking about. :(

Unless you're talking about redox reactions....

Unless you're talking about redox reactions....

See

a) There must be an oxidant and reductant present.

-_-;

I'm studying for my redox test on Tuesday.

Here's the only thing I can help you on about redox reactions since this is all they had asked usually and I had glossed over it majorly.

For each of the following, circle the combinations that will result in a redox reaction:

Cd (s) immersed in HBr (aq)

Pb (s) immersed in KCl (aq)

H2 (g) bubbled through Cu(NO3)2 (aq)

Mg (s) immersed in MnBr2 (aq)

My ditz of a teacher assistant, instead of explaining redox reactions to me when asked, simply told me a trick of the trade that works all the time when answering this kind of question. Consider the single elements listed to be the peasants of a kingdom. Then consider the first element of each compound listed as the kings of the kingdom. If the peasants rank higher on the series list than the kings, then it's a redox reaction because the peasants have now become reactionaries.

All except the second one are redox reactions. So like the first one, Cd (s) is the peasant and H is the king. Cd is listedabove H in the series list, hence it has reacted because as a peasant, it dared to rank higher than H, therefore there was a revolution aka a redox reaction.

Silly, I know. But it gave me the full four points for that question on my midterm without even understanding a thing about redox reactions.

OMG. I think I get it. ._.

THANK YOU. :D :D :D

Seriously. I have three tests on Tuesday, and I'm studying furiously for them. I really want to do well, especially after my last stellar performance in Chem. I was 1.5 marks off a perfect score on that Acids and Bases test.

IS there some drama person that can help me with some advice for my monologues (and acting skills in general)?

I still have this horrible problem where I can't keep a straight face. I mean, in practice, I can... but then if I perform it in front of people and they laugh at something funny I can't help not laughing or at least smiling myself.

Anybody have any tips? I'm in Drama 2 and after all this time I stil have trouble with it.

You could incorporate a natural reason for you to smile within the scene. Or you can try thinking of something sad.

You could try training yourself up to ignore the audience...have a bunch of your friends sit with you when you practice, and tell them to make a lot of noise so that you can get used to it.

Find a spot on the wall opposite you and focus on it. And the area around it. And practice with people around you so you'll look more natural. Eye contact is important. And don't rush it. XD

Or at the very least, electron configuration? Anyone?

Do you still need help Dimi?

Do you still need help Dimi?

Not yet. For this chapter, I was actually able to do almost all of the questions at ease.

But I'm having trouble doing the pre-lab assignment.

This one I have no clue what to do:

How would you compare the molar enthalpies of neutralization for a monoprotic acid, a diprotic acid, and a triprotic acid? Write the balanced chemical equations and include molar enthalpy values of each chemical reaction to support your conclusion.

I have no clue what those acids are nor what to do without any numbers to work with. :S

I'll be typing up the other questions in another post while you ponder about this.

In determining the heat of solution of a certain salt, a student found the final temperature of the solution was less than the initial temperature. Explain how it is possible for the solution to cool down this way.

Calculate the calorimeter constant given the following data:

Temperature of 50.0 g of hot water: 65.4 degrees Celsius

Temperature of 50.0 g of cold water: 15.5 degrees Celsius

Temperature after mixing: 35.8 degrees Celsius

specific heat capacity of water: 4.184 J/g K

My solution is as follows and I'd like for you to see if it is correct.

Qsystem = Qcontents + Qcalorimeter + Qreaction = 0

Qcontents = Qhot + Qcold = m X c X (delta Thot + delta Tcold)

= (50.0g)*(4.184 J/g K)*[(35.8 degrees C - 65.4 degrees C) + (35.8 degrees C - 15.5 degrees C)]

= -1945.56 J C/K = 7.148851736 J

Qcalorimeter = Ccalorimeter X delta Tcold

Ccalorimeter = Qcalorimeter/delta Tcold = -Qcontents/delta Tcold

Ccalorimeter = -(7.148851736 J)/20.3 degrees C = -3.52 X 10^-1 J/degrees C

How would you compare the molar enthalpies of neutralization for a monoprotic acid, a diprotic acid, and a triprotic acid? Write the balanced chemical equations and include molar enthalpy values of each chemical reaction to support your conclusion.

Right. I think monoprotic acid etc is basically the equivalent of monobasic, dibasic, and tribasic acids. These refer to the dissociation of the acids. A monobasic acid will dissociate to give one H+ per molecule. Examples of these would be HCl, HNO3. A dibasic acid will dissociate to give 2 H+ per molecule, like H2SO4 and H2CO3. And vice versa for tribasic acids, which would be like H3PO4.

Next thing to define would be the standard enthalpy change of neutralization, which is the change in enthalpy that occurs when an acid and a base undergo a neutralization reaction to form one mole of water under standard rtp.

Off the bat I can tell you the answers. 57KJ/mol for monoprotic, 114KJ/mol for diprotic, and 171KJ/mol of triprotic. This is because a monoprotic acid like HCl, reacts with NaOH to produce one mole of water.

HCl + NaOH = Na+ + Cl- + H+ + OH- (dissociation)

H+ + OH- = H2O (forms one mole of water)

For the balanced reactions, just use your own knowledge of acids and bases, and balance the equations. I've done the monobasic one, so you can go tackle the others.

I predict you will ask me where I got the values for the enthalpy changes. It's standard. Do enough questions, and you'll find that producing one mole of water will always give you 57KJ/mol. It multiplies by the number of moles of water formed. According to the equation. So you must always be careful when writing out your answers. Can you spot the error in my above sentences?

Qsystem = Qcontents + Qcalorimeter + Qreaction = 0

I think there's a little confusion here? Qcontents = Qcalorimeter is what you're trying to say right? Keep in mind that Q is enthalpy change.

I believe your solution is basically correct, although I do not understand your second last step,

Ccalorimeter = Qcalorimeter/delta Tcold = -Qcontents/delta Tcold

I do not see the need to change it to a negative sign. Can you explain to me why you did that?

I think there's a little confusion here? Qcontents = Qcalorimeter is what you're trying to say right? Keep in mind that Q is enthalpy change.

I thought Q simply meant heat (I'm using capital letter for this simply to make it easier to read and differentiate things on here). Also, since in this problem the Qreaction is equal to zero, then Qcalorimeter = -Qcontents with just a simple algebra.

I do not see the need to change it to a negative sign. Can you explain to me why you did that?

Because of my above explanation.

Well, from my understanding, we can never calculate the exact heat of something, and what we're calculating is always the heat change.

Also, since in this problem the Qreaction is equal to zero

How do you conclude that? Are you basing this on Qreaction = Qcalorimeter + Qcontents?

Well, from my understanding, we can never calculate the exact heat of something, and what we're calculating is always the heat change.

*shrugs* I really don't know.

How do you conclude that? Are you basing this on Qreaction = Qcalorimeter + Qcontents?

No, like this:

Qsystem = Qcontents + Qcalorimeter + Qreaction = 0 where Qreaction = 0

thus,

Qsystem = Qcontents + Qcalorimeter = 0

Qcontents + Qcalorimeter = 0

Qcalorimeter = = -Qcontents

And now for me to feel way dumber then all of you! ^^

I need help with my Algebra Homework. I'm in High School Algebra 2. eww.

I need help! I have to solve the quadratic equation, an I already have the answers I'm supposed to have, but no matter what I do, I can't get those answers! UGH!

Anywho, the problem is this:

X2-4X-8= -X2+X (Where the 2's are squares)

I'm supposed to get this answer:

-1, 2 2/3

Am I explaining this well enough?

I'm supposed to get this answer:

-1, 2 2/3

O RLY?

Let's check, then.

X be -1:

(-1)^2 - 4 * (-1) - 8 = - (-1)^2 + (-1)

1 + 4 - 8 = - 1 - 1

-3 = -2

Nope. Not in this universe.

You are not dumb, Ice. Your supposed solutions are simply not correct.

Or rather, I suspect your solutions are, but there is a typo somewhere in your formular.

Check if your second solution really is a solution as well. I'm to lazy to get out my calculator.

Or can't I read?

Damnitt. They're both not solutions...but...but...My book says they are! So...what does that mean?! Is the book wrong or are we doing something wrong?

Is the book wrong or are we doing something wrong?

The book is wrong. All we did was to replace the x with the supposed solutions.

You can check it the other way around:

X2-4X-8= -X2+X

x^2 - 4x - 8 = - x^2 + x ........... | + x^2; - x

2x^2 - 5x - 8 = 0 ..............| /2

x^2 - 5/2 x - 4 = 0

If you insert it into the pq-formula you'll get a negative value under the square root, which means your solutions are Imaginary numbers.

Thank you so much. This makes the...10th mistake that these books have. Our teacher is 10 more mistakes from writing the publishers and asking just what the fuck is going on.

x^2 - 5/2 x - 4 = 0

If you insert it into the pq-formula you'll get a negative value under the square root, which means your solutions are Imaginary numbers.

Huh? I'm blind. Of course, you don't get a negative value under the square root. Hello?! Brains?

You get 89/16 under the root. That's a positive value. Anyways. You can solve the calculation, but you won't get the book's solutions.

Your solutions should be ~ 3,6085 and ~ -1,1065.

You better not trust me after that blunder above, though. I clearly can't think straight.

Aaaa, so not imaginary numbers, but the book sol are still wrong. That's good...kinda.

Quick, somebody list the reasons why Antigone is a hero.

She stood up for what she believed in.

You can answer this by asking yourself this question: What did Antigone do that you personally probably wouldn't want to do?

Whoever drops by and can help me with my Chem homework. For this chapter, I am very happy to say that I was able to get 17 out of the 20 questions done without any help. Just these last three are giving me a bit of trouble now.

1. A ground state H atom absorbs a photon of wavelength 94.91 nm, and its electron attains a higher energy level. The atom then emits two photons: one of wavelength 1281 nm to reach an intermediate level and a second to reach the ground state.

A) What higher level did the electron reach?

B) What intermediate level did the electron reach?

C) What was the wavelength of the second photon emitted?

2. The following values are the only allowable energy levels of a hypothetical one-electron atom:

E6 = =2 X 10^-19 J

E5 = -7 X 10^-19 J

E4 = -11 X 10^-19 J

E3 = -15 X 10^-19 J

E2 = -17 X 10^-19 J

E1 = -20 X 10^-19 J

A) If the electron were in the n = 3 level, what would be the highest frequency (and minimum wavelength) of radiation that could be emitted?

B) What is the ionization energy (in kJ/mol) of the atom in its ground state?

C) If the electron were in the n = 4 level, what would be the shortest wavelength (in nm) of radiation that could be absorbed without causing ionization?

3) An electron microscope focuses electrons through magnetic lenses to observe objects at higher magnification than is possible with a light microscope. For any microscope, the smallest object that can be observed is one half the wavelength of the radiation used. Thus, for example, the smallest object that can be observed with light of 400 nm is 2 X 10^-7 m.

A) What is the smallest object observable with an electron microscope using electrons moving at 5.5 X 10^4 m/s?

B) At 3.0 X 10^7 m/s?

Sadly, I know next to nothing about chemistry. So I can't help you, Dimi.

Does anyone know how to read late Middle English? I can get the gist of some of it, but some words are just confusing.

3owre

yn haste 3e schul hit lete

Anybody know?

Antidifferentiate: x^2(3x^2-2x=(5/x))

._.

x^2(3x^2-2x=(5/x))

Using the distrubitive property, multiply through and you get this:

3x^4 - 2x^3 = 5x

Basic arithmetic:

3x^4 - 2x^3 - 5x = 0

Follow the rule of differentiation: [x^(n+1)]/(n+1)

(3/5)x^5 - (1/2)x^4 - (5/2)x^2 = 0

^Answer

Dimi: Extremely late thanks, but thank you. ^_^

New problem:

The sum of two positive numbers is 36. Use calculus to find the smallest possible value of the sum of their squares.

I've pretty much only got "Let x = one of the numbers. Therefore, the other one is 36-x."

Where do I go from here? ._.

Let one number be x and the other will be 36-x

The sum of their squares will be y = x^2 + (36-x)^2

Differentiate the above equation.

dy/dx = 3x - 72

Let dy/dx = 0 to find the minimum point on the curve

3x - 72 = 0

3x = 72

x = 24

Therefore, the smallest possible sum of their squares would be 24^2 + (36-24)^2

Oh no way. You are awesome. :D Thank you! ^_^

Oh no way. You are awesome. :D Thank you! ^_^

*blushes* Not really. I did fail Math rather spectacularly during June. Do you need me to explain, or is it okay?

It's okay. :)

Please.

Someone help me understand feudalism. Like... a short, simple summary of it would be very, very helpful. They keep tossing the word around in my book and giving me hints and I don't know straight up what it is.

Feudalism is a socioeconomic political system in Medieval Europe.

It's where a person is granted land by a person ranking higher than him in exchange for military service. You have the king as the highest being in the ranks. Beneath him are the barons who are his tenants-in-chief. They take care of his land, helping themselves to the stuff being provided on it (i.e. housing/shelter and food) as well as the king's support. The king, in turn, receives their military service and loyalty. Beneath the barons are the knights. The barons lease a portion of the land given to them by the king to the knights who also retain that land and receive housing and food from it while giving loyalty and military service in return. And then there are other below the rank of the knights and the same thing happens as well.

So it's a hierarchal system that allows people to receive a place to live and suppor themselves while giving the king a mass amount of support and loyalty.

Okey dokey. I get it. Thank you. :)

Anytime.

Okey dokey. I get it. Thank you. :)

Okay. Okay. A Chem question, for those Chemistry people out there. ;)

Octane burns according to this equation: 2C8H18(g) + 24O2(g) --- 16CO2(g) + 18H2O(g)

What mass of octane must have been used if 50.0 L of CO2, measured at 120 degrees Celcius and 1.10 atm, was produced?

**120 degrees Celcius is 393 Kelvin, and 1.10 atm is 112 kPa, just to save time if you need them in those measurements**

:S

I have no idea how to solve that problem...

First, I was going to solve it like I would for a combustion problem but octane already has its moles included.

Sorry I couldn't help you there, Sao. :(

Anyways, anybody know how to solve for lattice energy? I've been staring at it for like the past hour and it still is not making any sense to me.

Shit, is that gas law Sao? I suck at that.

pV=nRT is the general equation from what I remember. So plug in the values using stoichio and the equation you've already been given. I don't have me calculator now, and I'm really bad at gas law, so that's the most I can help you with.

Dimi-love, I should be able to help for Lattice Energy, on the other hand. I'm better at that.

Dimi-love,

Have you been talking to Sao a lot lately? XD

I should be able to help for Lattice Energy, on the other hand. I'm better at that.

Sweet! Well, what are you waiting for, woman? Hop to it! ;p

Just do it during your day hours and not during the night.

Oh and I have a Chem midterm this Friday. It's on three chapters most of which I understand. Should I need anything, can I count on you to be around this week?

Have you been talking to Sao a lot lately? XD

Yes, Dimi-love. Sao is on the same side of the globe you see. Only 3 hours or so ahead of me.

Sweet! Well, what are you waiting for, woman? Hop to it! ;p

Roger that, MA'AM!

Just do it during your day hours and not during the night.

I can just wake up a little earlier or sleep a little later. It's my holidays, don't worry about it!

Oh and I have a Chem midterm this Friday. It's on three chapters most of which I understand. Should I need anything, can I count on you to be around this week?

Sure thing. I should be free the whole of this week. Except Thursday, which should be your Wednesday. I won't be free then. I've got volunteer work going on. Till then, YOU get to WORK so you can ACE that TEST, got that? Don't embarrass me now, oh-minion-of-mine.

1. Forums are not to be used to post stories.
2. All discussions including language and content must be suitable for teens.
3. The owner/moderator(s) of this forum is solely responsible for content posted within this area.
4. All forum abuse must be reported to the moderator(s).

1. Forum admin/moderator
2. Fanatic (on site for more than 2 years)
3. Fan (on site for more than a year)
4. Regular (on site for more than 6 months)
5. Camper (on site for more than a month)
6. Apprentice (on site for more than a week)
7. Newbie (on site for less than a week)