# Recent content by needingtoknow

1. ### What is the format for ionic lewis structure w/ resonance?

Homework Statement I need to draw NH4NO2 which is an ionic compound. 3. The Attempt at a Solution NH4 is fairly straightforward to draw, with one N in the middle and four H surrounding, and no lone pairs. The problem comes with NO2- which is one nitrogen bonded to two oxygens. However, one...
2. ### For f(x) = abs(x^3 - 9x), does f'(0) exist

Thanks a million! This made perfect sense
3. ### For f(x) = abs(x^3 - 9x), does f'(0) exist

Homework Statement For f(x) = abs(x^3 - 9x), does f'(0) exist? The Attempt at a Solution [/B] The way I tried to solve this question was to find the right hand and left hand derivative at x = 0. Right hand derivative = (lim h--> 0+) f(h) - f(0) / h = (lim h--> 0+) abs(h^3 - 9h) / h...
4. ### Related rates question involving volume of cone

The formula is correct I just mislabelled it. I meant to say that V = pir^2 (4/3) -- volume of a cone when h = 4.
5. ### Related rates question involving volume of cone

Homework Statement Sand falls from a conveyor belt at the rate of 10m^3/min onto the top of a conical pile. The height of the pile is always 3/8ths of the base diameter. How fast is the radius changing when the pile is 4 m high? 3. The Attempt at a Solution V = pir^2 (4/3) -- volume of a...
6. ### Applying Coulomb's law to HCl and LiF

So electronegativity is the tendency of an atom to attract electrons in a bond. We know that fluorine has a greater electronegativity than lithium and therefore attracts more electrons. In HCl chlorine is more electronegative than hydrogen. For LiF the electronegativity difference is greater...
7. ### Chemistry Understanding the reasoning behind the mole

Thank you all for your answers, a combination of Borek's and ePenguin's answer really cleared my confusion.
8. ### Chemistry Understanding the reasoning behind the mole

All right epenguin I'll address what you said first. So in my scenario there are two samples of two different elements. One sample is of aluminium and the other sample is of americium. The reason why the numbers are wrong is because I changed the elements at the last moment and forgot to change...
9. ### Applying Coulomb's law to HCl and LiF

So are you saying that +1 and -1 and 0.17 and -0.17 are determined experimentally. Secondly are they charges so does that mean that the lithium atom has a charge of 1 C and the fluorine atom has a charge of -1 C. If so what is the explanation for why the one with the ionic bond had such higher...
10. ### Chemistry Understanding the reasoning behind the mole

Homework Statement My book says that if the ratio of the masses of the samples is the same as the ratio of the masses of the components then the two samples contain the same number of components. That part makes sense. But how do we know that the same number of components has to be 6.02 x...
11. ### Applying Coulomb's law to HCl and LiF

Homework Statement During a chem lesson my professor was demonstrating Coulomb's law using HCl. Fe = kq1q2/r^2 so what he did was he replaced q1 and q2 with 0.17 and -0.17. Then he showed an example with LiF and then replaced q1 and a2 with 1 and -1. I think he was trying to...
12. ### If two lenses have the same radii of curvature but different indexes

Homework Statement If two lenses have the same radii of curvature but different indexes of refraction their focal lengths won't be equal because the one with the greater index of refraction will undergo greater refraction and will have a smaller f. Doesn't this contradict the definition of...
13. ### Would you hear nothing if you struck two tuning forks of the same

Oh I thought you meant to play two separate sounds from two separate speakers, but what you're saying makes sense. I tried it with opening this in two separate tabs but I didn't get any cancellation. I heard some beats though or at least I think I did.
14. ### Would you hear nothing if you struck two tuning forks of the same

phinds Oh ok plus because the sound would probably reflect off of other surface and eventually reach your ear. No mfb unfortunately I cannot try that experiment now b/c I'm at a laptop which has a single source of sound. I'll try to do that if I ever gt my hands on a desktop computer though...
15. ### Would you hear nothing if you struck two tuning forks of the same

Homework Statement Would you hear nothing if you struck two tuning forks of the same frequency at the same time or if you struck one some amount of seconds after the other which would result in one fork's sound wave to be exactly pi out of phase of the other?