CHEMISTRY COMMUNITY

America Alvarado

I had the same question, thank you!

America Alvarado

thank you for your help!

America Alvarado

how do we answer part (a)?

America Alvarado

yayy, thank you!

America Alvarado

When is the last chem lecture?

America Alvarado

A new favorite is Costco's triple chocolate brownie! a must for intense chocolate lovers :P

America Alvarado

thank you!

America Alvarado

The final is always cumulative right? Or is it like the midterms where we only focus on like new material

America Alvarado

when's spring break?

America Alvarado

is there any homework this week? I don't see anything on Sapling.

America Alvarado

never mind, I got it lol. I had put H2O as aqueous instead of liquid.

America Alvarado

So, I added the phases given and I'm getting the wrong answer on sapling, did anyone else have this problem?

America Alvarado

How do we assign phases onto balanced equations? For example, this is the equation given

N2H4(g)+ClO−3(aq)⟶NO(g)+Cl−(aq)

and i know this is it balanced

3N2H4 + 4ClO3- → 6NO + 4Cl- + 6H2O

America Alvarado

I am confused on how to balance the equation, can someone help please. The question is:

For a particular redox reaction, NO−2 is oxidized to NO−3 and Cu2+ is reduced to Cu+ . Complete and balance the equation for this reaction in basic solution.

America Alvarado

Is the drop in from 1-3 on thursdays canceled today?

America Alvarado

Hello, if anyone is in Dis 1E Wednesday from 2-2:50pm and wouldn't mind switching to Dis 1B from 2-2:50pm please let me know (: I really need a switch.

America Alvarado

I love pazookies, brownies, and anything delicious and sweet honestly. omg im hungry now

America Alvarado

It's kind of comforting to know I'm not the only one. I recently had to take up 2 jobs and balancing school and work has not been easy. I feel so burned out and exhausted all the time. I just hope all this work and effort is worth it in the end.

America Alvarado

Did Lavelle mention what questions from sapling relate to the midterm coming up? I know for the last midterm he did.

America Alvarado

In addition to this, a UA said you would use the G° equation when the reaction you're working with is at equilibrium and the equation for G when it is not since G is the difference between gibbs free energy of products and reactants at any point.

America Alvarado

The textbook problems related to midterm 2 material is under outline 3 and outline 4 of the syllabus posted on his website. Remember to exclude the questions that were covered on midterm 1 in the third outline. Hi, I noticed you said exclude the questions covered on midterm one. does this mean that...

America Alvarado

Thank you, I just noticed that

America Alvarado

Why is R= 0.0820578 and not 8.206 like it is on the constants sheet we have?

America Alvarado

thank you!

America Alvarado

I don't understand where the 6 - 7.5 came from. Can someone explain please

America Alvarado

The book answer says this but I'm plugging it into the calculator and I'm not getting the same answer

America Alvarado

How do we find What percentage of the heat is used to raise the temperature of the water?
I know q(water)= 1*10^5 and q(copper)= 1.2*10^4

America Alvarado

what is the difference between monatomic and diatomic? Hi! Monoatomic means that the molecules in an element are made up of one atom, which diatomic means that the molecules in an element have two atoms bonded together. Noble gases are some examples of monatomic elements, while H2, N2, and F2 are s...

America Alvarado

Is anyone taking Chem 14BL, B and physics? I wanted to know if its too much to take at the same time.

America Alvarado

I'm really nervous as well but I'm trying to do my best and stay positive.

America Alvarado

what is the difference between monatomic and diatomic?

America Alvarado

Sometimes this happens to me as well. I usually close the tab and open up ccle all together and it works.

America Alvarado

They usually do reviews for the midterm coming up.

America Alvarado

Does anyone know who counts our posts? because I think I'm missing points and wanted to see who I should go to

America Alvarado

Hello, I'm little confused on what exactly this problem is asking us to do and what it wants us to do with the table? Would it be possible for anyone to explain to me how were supposed to use it? Thank you! Hey! so for this problem you use q=m*deltaH to find delta H. From the table you find the dif...

America Alvarado

they are but i think the practice problems he assigns from the book are more helpful. He sometimes puts those same problems in the test.

America Alvarado

I was just going to ask about this problem! thank you

America Alvarado

I think it is because in path A the ideal gas goes through a reversible expansion so you use w=-nRTln(v2/v1) whereas in path B the gas undergoes an irreversible expansion so you'd use w=-P delta V. Hope this helps (:

America Alvarado

I believe for q(water) you would use (T final- 45 degrees C) and for q(ice) you would use (T final- 0 degrees C)

America Alvarado

thank you so much for these tips!

America Alvarado

thank you!

America Alvarado

Don't trust atoms, they make up everything...

America Alvarado

Thank you! I needed to hear this (:

America Alvarado

Yea I was just going to ask the same thing because I feel like we haven't had enough time to really learn this week's topic since we're having the midterm.

America Alvarado

The question says to use the equilibrium constant found in the table below for H2 + I2 = 2HI. Does anyone know why the K=160 and not 794?

America Alvarado

So for part c (or the last question), you will want to use the equation you listed (but use CS2 instead of S8): ΔH=nCS2×ΔH∘ Since 399 kJ of heat is absorbed, this will be the value for ΔH. Then use the value of ΔH∘ given in the problem, which is +358.8, and divide this by 4 because there are 4 mole...

America Alvarado

If this is given Carbon disulfide can be prepared from coke (an impure form of carbon) and elemental sulfur. 4C(s)+S8(s)⟶4CS2(l) ΔH∘=+358.8 kJ how would we answer these questions? 1)Calculate the amount of heat absorbed in the reaction of 173 g of carbon with excess sulfur. 2)Calculate the amount of...

America Alvarado

I love going on Disney plus and watching Soul or Mulan to calm my nerves

America Alvarado

thank you!

America Alvarado

how do we find the percent ionization?

America Alvarado

Is percent ionization but the Ka as a percentage?

America Alvarado

I thought they were missing too but you have to make sure you're looking at 5G.1,3... these start on the pdf page 243. Hope this helps!

America Alvarado

Are you plugging in the correct value? Your question says NH3's concentration is 3.88 mol * L-1, but you are plugging in 3.33 instead into your equation. If you do (3.88)^2/[(0.569)(2.76)^3], you should get 1.2584, and that rounds to 1.3? Because 1.3 (Q) is larger than 0.061 (K), the reaction is mo...

America Alvarado

Hey, haas anyone solved q6? its asking for Q and I know its the same as solving for K but the answer I'm getting isn't correct. I'm not sure what I'm doing wrong. The question is: Consider the reaction at 500°C . N2(g)+3H2(g)↽−−⇀2NH3(g)Kc=0.061 If analysis shows that the composition of the reaction ...

America Alvarado

Is this why on the sapling feedback the ice box shows reactants asa +x? I have been trying to solve it for the longest and still don't understand. I keep getting imaginary numbers as my x.

America Alvarado

The Harry Potter series, specifically the first two and the og Disney Mulan are my comfort movies. Something about them just make me feel safe lol

America Alvarado

thank you all!

America Alvarado

In 1/11 lecture, Lavelle says Kw= 1.0 x 10^-14 therefore H30 and OH must be 1.0 x. 10^-7. How did he come up with 1.0 x 10^-14?

America Alvarado

Nicole Critzer 2L wrote:In order to get points for each post does it matter how long or short it is? Or is a question or like two sentences sufficient?

I don't think it matters as long as you're participating, but writing really thorough posts will help you make up missed posts.

America Alvarado

Was the one from 8-10pm cancelled? I've been waiting for the zoom call to start for 30 minutes.

America Alvarado

thank you!

America Alvarado

When do UA sessions officially start?

America Alvarado

Is there any Sapling modules due Week 1?

America Alvarado

The test was way harder than I expected, but I hope we all did well (:

America Alvarado

thank you!

America Alvarado

How do we determine if a salt is acidic, basic, or neutral?

America Alvarado

America Alvarado wrote:How do we calculate the [H+] and [OH-] if we are only given the pH. For example, pH of 8.85 at 25 °C.

I think I figured it out, would we do 10^(-8.85) to find [H+]?

America Alvarado

How do we calculate the [H+] and [OH-] if we are only given the pH. For example, pH of 8.85 at 25 °C.

America Alvarado

Is anyone else having trouble playing today's lecture? (12/7) I keep trying but its just a black screen that says "this video file cannot be played"

America Alvarado

Thank you!

America Alvarado

Does anyone know or know where I can find the password for the chemistry website?

America Alvarado

Thank you soo much for all your help! I finally understand!

America Alvarado

Do acids and bases have anything to do with the electronegativity of an atom?

America Alvarado

How do you calculate the coordination number? I'm really lost.

America Alvarado

Where are the dates for the test?

America Alvarado

single bonds are sigma and every double bond contains one sigma and one pi bond

America Alvarado

What happens if we give up on a question? Do we lose the points for that question?

America Alvarado

In lecture, Dr. Lavells referred to many "unhybridized orbitals". How exactly can you identify these? Well hybridized orbitals are a combination of atomic orbitals, so unhybridized orbitals would be the left over orbitals that are not combined, or the ground state of the atom. Hope this h...

America Alvarado

I had a follow-up question to this discussion thread, is there a maximum number of electrons an expanded octect can accommodate? I had read somewhere that it depends on how many orbitals the valence shell of an atom has. If it has more orbitals free then it will be able to accommodate more electron...

America Alvarado

So are the oxidation numbers usually given? or are we suppose to know that Oxygen has an oxidation number of -2?

America Alvarado

thank you! I understand now

America Alvarado

Correct, like Lucy said, since there is no bond between hydrogen and carbon there are hydrogen bonds

America Alvarado

Is there a way to make up posts points missed?

America Alvarado

What are London dispersion forces ?

America Alvarado

How do you determine the oxidation number of a molecule? For example the oxidation number of ClO4-? Thank you

America Alvarado

Thank you everyone!

America Alvarado

So the more valence electrons an atom has, the higher its electronegativity?

America Alvarado

How do you draw resonance lewis structures? Like how do you know where to put double or single bonds or how to you rearrange a structure so it's still similar? I'm having a hard time answering the hw question asking for two resonance structures of a carbamate ion.

America Alvarado

I was wondering the same thing. I'm going to ask the TA during discussion.

America Alvarado

This quarter feel so long. I feel exhausted and I'm having a harder time understanding the material after Midterm 1. I don't know if anyone else feels the same.

America Alvarado

Does anyone know if there is discussion section on Wednesday since it's Veterans Day?

America Alvarado

This may sound weird, but it really helps me. To stay focused I talk to myself about whatever I'm studying. If I write something down I also say it out loud like if I were explaining it to someone.

America Alvarado · Re: Homework due date Sampling homework is always due Sunday night at 11:59pm

Sampling homework is always due Sunday night at 11:59pm

America Alvarado

Omg these are actually funny

America Alvarado

What would the speed of each particle be if it had the same wavelength as a photon of orange light (lambda=625.0 nm)? Did anyone else have trouble finding electron and alpha particle speed using the de Broglie's equation? I converted nm to m and used v= h/m*lambda but I keep getting the incorrect an...

America Alvarado

Yea, you're right. You use E=hc/lambda. Then you multiply 32W times 2 because it's asking in 2 seconds. Then you divide 64W by what you got from E=hc/lambda and that is how many photons are generated. For the second part, you use Avogadro's constant to find the moles. Hope this helped!

America Alvarado

Francesca_Borchardt_2L wrote:Hello,

They are located towards the end of the textbook. The odd exercises answers are there. Page C12 is where the answers are.

Hope this helps!

Thank you!

America Alvarado

Does anyone know where to find the textbook solutions to the practice problems?

America Alvarado

Ground state electron configuration is when the electron is at its lowest energy available. For instance the ground state configuration for oxygen would be 1s2 2s2 2p4. But let's say you excite it, then the electron will move up a quantum level to another orbital. So the excited state configuration...

America Alvarado

Hi, can someone explain the ground state electron configuration? I don't know the difference in written configuration between excited and ground state.

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