##### Chemistry Word problem Need Help!

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The atomic mass of platinum is 195.1. A cube of platinum weighs 24.8g and its density is 21.45g/cm^3.

Calculate.

If we consider the sample is composed of spherical atom each with radius r and volume Vatom =4/3Pir^3, and if we assume that the total volume of the spheres in the sample is 74% of the total volume, calculate the radius of a single platinum atom in picometers.

Oct 7th, 2015

the no. of atoms in one mole = 6.022 x 10^23

no. of atoms in 24.8 g of platinum = 7.65 x 10^22 atoms

the volume of atoms = 24.8 / 21.45  = 1.156 cm^3

the net volume of atoms = 0.74 x total volume = 0.74 x 1.156 cm^3 = 0.855 cm^3

i am still working. please be patient. thank you. :)
Oct 7th, 2015

now the no. of atoms = 7.65 x 10^22 atoms

so the total volume = 7.65 x 10^22 x 4/3Pir^3 = 0.855

so, r = 1.38x 10^-8 cm

r = 138 picometers.

Oct 7th, 2015

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Oct 7th, 2015
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Oct 7th, 2015
May 29th, 2017
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