Recent content by erjkism

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    Why does melting point decrease for impure solid?

    ahhh... i see thanks man
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    Why does melting point decrease for impure solid?

    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??
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    Show series [sin(n)]/n converges?

    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!
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    Strange infinite series problem using integral test.

    yea it is
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    Show series [sin(n)]/n converges?

    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
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    Strange infinite series problem using integral test.

    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
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    Show series [sin(n)]/n converges?

    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
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    Strange infinite series problem using integral test.

    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
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    Show series [sin(n)]/n converges?

    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...
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    How Do You Calculate the pH of a 8.57x10^-10M HNO3 Solution?

    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
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    How Do You Calculate the pH of a 8.57x10^-10M HNO3 Solution?

    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...
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    Surface area of revolution for an ellipse

    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
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    Chemistry Can the amount of moles in a mixture be determined using mass and molar mass?

    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...
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    Anticipated pH of Buffer Solution ( )

    k i finally got the answer thanks anyone who looked at it tho
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    Chemistry Can the amount of moles in a mixture be determined using mass and molar mass?

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