 Chemistry Help Forum Face centered cubic question
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 Thread Tools Display Modes Dec 7th 2016, 09:04 PM #1 starrysky Junior Member   Join Date: Oct 2016 Posts: 10 Face centered cubic question The atomic radius of metal X is 1.50 × 102 picometers (pm) and a crystal of metal X has a unit cell that is face-centered cubic. Calculate the density of metal X (atomic weight = 42.3 g/mol).   Dec 8th 2016, 01:26 PM   #2
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Posts: 75 Originally Posted by starrysky The atomic radius of metal X is 1.50 × 102 picometers (pm) and a crystal of metal X has a unit cell that is face-centered cubic. Calculate the density of metal X (atomic weight = 42.3 g/mol).
The main concept here is to find the density of the material...ie. from a single unit cell. So for an FCC crystal how many atoms of X are in the unit cell? What are the dimensions of the unit cell? So now you know the density in terms of # of atoms/volume in a unit cell. The rest is unit conversions.

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-Dan
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Answer: Seawater   Apr 16th 2019, 11:15 PM #3 chemistrystudy Junior Member   Join Date: Jan 2019 Location: India Posts: 7 We know that σ = (Z × M)/(N × a³) Here, Z = 4 for fcc cubic Crystal, M = 42.3 gm/mol and N = 6.023 × 10²³ and a = 1.50 × 10² pm = 1.50 × 10⁻⁸ cm Putting the value on the above equation to calculate the density of the crystal X.  Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode 