Question:

ap chem is so hard!?

Calculate the average density of a single Al-27 atom by assuming that it is a sphere with a radius of .143 nmThe masses of a proton, electron, and neutron are 1.6726x10^ -24 g, 9.1094x10^ -28 g, and 1.6749x10^ -24 g, respectivelyThe volume of a sphere is (4)(pie)(r)^3Express the answer in grams per cubic cmThe density of aluminum is found experimentally to be 2.7g/cm3(hint- first you need to figure out how many protons neutrons and electrons are in an Al-27 atom, then figure out the mass of the whole atom, then figure out the volume of the atom using the given radius and the volume formula, so you can use the mass and volume to do the density)Even with the hint i am clueless!

Answer:

so find volume of aluminum first radius of molecule .143 nm .143 x 10^ -9 m 1.43x10^-8 cm V 4 (pi) (1.43x10^-8 cm)^3 3.675 x 10^-23cm^3 you wanted to convert it because your density is by cubic cm laterthen calculate the total mass from your given infoAl 27 has 13 electron 13 proton and 27 neutron mass of total proton: 13(1.6726x10^ -24 ) 2.174 x 10^-23 g mass of total electrons : 13(9.1094x10^ -28) 1.18422 x 10^-26 mass of total neutron: 27(1.6749x10^ -24) 2.1774 x 10^-23g add the mass , total mass: 4.3529 x 10^-23 g density: mass/volume 4.3529 x 10^-23 g/ 3.675 x 10^-23cm^3 and you get 1.18 g/cm^3 it seems a bit off from the experimental value, which is possible, but mostly likely i type in a number wrongDON'T trust my algebra and calculator plugging skill :) but i can guarantee the method is correct AP chemistry really isn't that bad, don't listen to the stories :)i recommend the books: princeton review and 5 steps to a 5 (- that last book saved me when i took it, raised my score of 2 to a 4 in a week)
well a cheap conair one is pretty good though! ]
yea its good, but the CHI works well too
use not that iron there is this iron called hot tools professinal ceramic my hair is CURLY and it straightens super out of this world good! try it+ its not expensive

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