Recent content by erjkism

ahhh... i see thanks man

Okay, i am doing a lab involving crude acetaminophen and pure acetaminophen. The crude acetaminophen is supposed to have a lower melting point than the pure acetaminophen... how does that work and why? does it have to do with thermodynamics or what??

no, our teacher told us that we have the ability to do it, but it is just pretty difficult. he won't help me... someone save me!

yea it is

its just a problem that i need to do for calculus 2 at college... so i don't know much more than what's been talked about here already

i did the u substitution, u =nlnn and i get \int\frac{1du}{u} which just becomes [lnu] which becomes: [ln(lnlnn)] evaluated from 27 to 10^100,000

okay so i tried that, but I'm having a tough time figuring out the result of that limit. \frac{n sin(n+1)}{(n+1)sin(n)} I am still stuck with a bunch of sin functions... I am not sure if this is the right thing to do

Homework Statement I need to show that \Sigma\frac{1}{nlnnlnlnn} from n=27 to n=10^(100,000) is approximately equal to 8.1

Homework Statement \Sigma\frac{sin(n)}{n} from n=1 to infinity i have to show that this series converges, but that it doesn't converge absolutely. Homework Equations the thing is, I figured th The Attempt at a Solution if you say that the top of the equation is...

yeah that's what i mean. that's why this problem is getting difficult. if you just change the concentration of nitric acid to the H3O+ concentration, you get a pH above 7.. which is wrong

Homework Statement I have to find the pH of a 8.57x10-10M HNO3 solution. Homework Equations HNO3 + H20 <--> H3O+ + NO3- pH= -log[H3O+] The Attempt at a Solution my theory was that the hydronium ion concentration would be the hydronium ion concentration in water (1x10-14 M) plus the...

Homework Statement Find the surface area obtained when the upper half of the ellipse: \frac{x^{2}}{4}+ y^{2}=1 is rotated about the x-axis Homework Equations \int2piyds The Attempt at a Solution

well.. that is sort of impossible to say the total moles of "solution present". for example, try making up your own values for a solution... like 20% A (molar mass 20) and 80% B (molar mass 5). you could then find find moles A and moles B and add them up together to find total moles. now...

k i finally got the answer thanks anyone who looked at it tho

i don't think you can really do that... mainly because you don't know what fraction of the mixture is NaCl or C12H22O11.