Recent content by Rujano

Hello! I'm having a hard time understanding the acidity and basicity of amino acids. I read this: the acidic group in an amino acid is NOT the -COOH but the NH3+ and the basic group is COO- and not the NH2... why? Thanks in advance!

Homework Statement Hi. I'm starting to read about IR spectroscopy and I have a question. I know that there are 2 kinds of vibrational modes in molecules: bending and stretching, so in a molecule like water for example, how can I tell which one of the vibrational does it have? What I mean...

Homework Statement Hi. A patient produced 1122 mL of urine in 24 hours. A 1.00-mL aliquot of the sample was treated with Mo(Vl) and ascorbic acid and was diluted to a volume of 50.00 mL. A calibration curve was pre- pared by treating 1.00-mL aliquots of phosphate standard solutions...

Homework Statement Hi. I have a table where there is an absorbance for a 0.00 concentration (blank). I now that I have to substract that value to to each of the other absorbances that I have, but my question is... Do I have to graph (concentration 0.00, absorbance 0.00) in the calibration...

Thanks! I got it now

Thanks again. When I google that I get a bunch of labs reports that show experimental data about it. However, my question is why do I only have to take into account the phosphate instead of the whole complex that is formed? Take a look at this please: The monitoring of phosphate involves the...

Hi. Thank you for your reply. What would be the stoichometric reaction, though? (I mean, why is to proportional to the concentration oF Phosphate instead of the whole complex?)

Homework Statement Hi. I know this will sound silly, but I really don't get it.Let's say that I want to determine phosphate in a given sample by using molybdate. . After plotting the calibration curve using the absorbance and concentration of the phophate standard, I calculate the...

Homework Statement Hi. If I have 3 mL of a Fe3+ solution (0.0007 mol/L) and that is treated with SCN- to form a complex and then is diluted until I have 100 mL of a solution. What would be the final concentraton of that solution? Homework Equations C1*M1= C2*M2 The Attempt at a...

Homework Statement Hi. I'm pretty much a beginner in organic chemistry and I'm just wondering something. For example, I know that HCl is a stronger acid than HF. But... then why the following happens if a have an organic acid (e.g a carboxylic acid)? According to what I see, a...

Homework Statement Hi. The combination of Fe(II), H2O, Cl- y NH4+ yields 3 coordination compounds, one of which is: [Fe(H2O)6]Cl2 Which are the other ones? Homework Equations The Attempt at a Solution Even though I sort of know how the compounds could be formed I don't why or rather , how...

Hi. I was just wondering about this because is most texts I've seen this one: Tf/Ti = (Vi/Vf)^y - 1 y= gamma (Cp/CV) However, in my worksheets I always see this one: Tf/Ti = (Vf/Vi)^1 -y And actually, when I tried to solve one problem, I tried to use the first one but the...

Thank you again! I can't believe that I skipped that. So, the final correct answer would be that: * q = 0 * U = -3873.4 J * w = 3873.4 J U negative and w positive

Oh thank you. I see it now. It was 1 - y and I forgot about doing this: 1 - 1.4 = - 0.4 So it plug into the equation the -0.4 instead of the 1.4 It get 113.6 K (final temperature) So dT would be: 113.6 K - 300 K = - 186.4 K That means that the Internal Energy is NEGATIVE...

Hello everyone. I would like to know if I did this correctly. Homework Statement Calculate the heat, internal energy and work of 1 mol of hydrogen, which undergoes a reversible adiabatic expansion from a volume of 5.25 m^3 at 300 K to a volume of 25.5 m^3 The Attempt at a Solution...