Recent content by samdiah

Please.

Homework Statement I have attached the IR and NMR spectrum from lab. I have determined that there was a nitrogen present in the compound. There was no sulfur or halogens. The molecular weight was 138. The compound was solid and yellow color. It had a melting point between 124 and 134 C...

Thank you so much. I got it at last.

It is asking for initial concetration. The reason that pH is not 7 because weak acid doesn't dIssacoiate fully. Would u guys recommend me to read anything to do this. I did all the reading assigned by my Prof and they only have to do with Ka's and pH nothing about 1st and 2nd Volumes...

I did use stoichiometry the whole time, but keep getting all sorts of wrong answers. I subtracted the 1st eq pt from 2nd to get V required to titrate only the biphosphate. I use this V and NaOH to get moles of NaOH. Since the mole ratio is 1:1, I say that moles of bi phosphate is also same. Use...

What I was thinking of the hint was that H2PO4- is the other substance present. If there was no biphosphate then the 2nd equivalence point will be less then 2xV1, because 1 phosphoric acid=2OH. "Hint 2: are you asked to calculate the concentration of phosphoric acid?" No we r asked to...

This is the only information given. We r not suppose consider other acid. Just the biphosphate and phosphoric acid. I am doing this question in 6 different ways and it doesn't yield the correct answer. I also got 1.533x10-3 a few times now.

This is the reaction for first endpoint: H3PO4(s) + H2O(l) ⇌ H3O+(aq) + H2PO4–(aq) Ka1= 7.5×10−3 This is the reaction for second endpoint: H2PO4–(aq)+ H2O(l) ⇌ H3O+(aq) + HPO42–(aq) Ka2= 6.2×10−8 This is the third, but it cannot be seen: HPO42–(aq)+ H2O(l) ⇌...

Homework Statement The phosphoric acid in a 100.00 mL sample of a cola drink was titrated with 0.1029 M NaOH. The first equivalence point was detected after 13.34 mL of base added, and the scond equivalence point after 28.24 mL. Calculate the concentration of H2PO4- in mol/L. (Hint: if only...

Homework Statement Find the wave function of particle in a 1-dimensional potential Well of length L, n=2 and mass m Homework Equations I think this would be the wave equation, but not 100% sure [tex]\varphi=Asin(n\pix/L)[\tex] where n=1,2,3... tex doesn't work for me---=Asin[n*pi/L] The...

I found the two derivatives and I found that the function φ(x) = A sin(2x) + B cos(2x) is an eigenfunction of the Hamiltonian operator: H=-h2 d2 2m dx2 and the proportionality constant is 2h2 m Can someone confirm with me if this is right or what did I do...

can someone please help and give me clues.

The harmonic oscillator is a model for the vibrating diatomic molecule. The energy expression for this model is given by: Ev = (v+1/2) hν v = 0, 1, 2, 3,… (ν = oscillator frequency) Use this expression to predict the wavenumber (cm-1) position of the infrared absorption due to the...

I am a seond year Quantum Chemistry student. I am having a hard time understanding these concepts. I was wondering I can get help in this concept. How can it be demonstrate mathematically in the Hamiltonian operator that the function φ(x) = A sin(2x) + B cos(2x) is an eigenfunction of...

Homework Statement Identify the type of natural selection (distruptive, stabilizing, directional, sexual, runaway or cummullative) operating in these examples: a) The diversity among honey creepers b) Peacock’s tail c) Central nervous system d) Egg size in robins e) Body...