Comments on: How do you calculate the density of a body centered unit cell? http://molybdenuminfo.com/2008/08/12/how-do-you-calculate-the-density-of-a-body-centered-unit-cell/ Answering your molybdenum questions Fri, 10 Sep 2010 22:54:28 +0000 http://wordpress.org/?v=2.6.3 By: mRNA http://molybdenuminfo.com/2008/08/12/how-do-you-calculate-the-density-of-a-body-centered-unit-cell/#comment-57 mRNA Mon, 18 Aug 2008 10:43:56 +0000 http://molybdenuminfo.com/?p=68#comment-57 The density of the unit cell, ?, is given by: ? = ZM / a³N ; where Z is the formula units per unit cell, M the molar mass per formula unit, a the cubic unit cell lattice parameter, and N the Avrogadro constant. For bcc, Z = 2 For molybdenum, M = 95.94 g mol?¹ and a = 314.1 pm = 314.1 x 10?¹² m Substituting gives, ? = (2)(95.94) / {(314.1x10E-12)³(6.022x10²³)} = 1.03 x 10E7g m?³ = 10.3 g cm?³ The density of the crystal is 10.3 g cm?³ (to 3 s.f.). The density of the unit cell, ?, is given by:

? = ZM / a³N ;
where Z is the formula units per unit cell, M the molar mass per formula unit, a the cubic unit cell lattice parameter, and N the Avrogadro constant.

For bcc, Z = 2
For molybdenum, M = 95.94 g mol?¹
and a = 314.1 pm = 314.1 x 10?¹² m

Substituting gives, ? = (2)(95.94) / {(314.1×10E-12)³(6.022×10²³)}
= 1.03 x 10E7g m?³
= 10.3 g cm?³

The density of the crystal is 10.3 g cm?³ (to 3 s.f.).

]]> By: paul1 http://molybdenuminfo.com/2008/08/12/how-do-you-calculate-the-density-of-a-body-centered-unit-cell/#comment-56 paul1 Sat, 16 Aug 2008 21:17:29 +0000 http://molybdenuminfo.com/?p=68#comment-56 How many atoms are there in a body centered cubic cell? What do those atoms mass to? Convert this number to grams. What is the volume of a cube which is 314.1 pm on an edge? Convert to cm³. Divide mass by volume. How many atoms are there in a body centered cubic cell? What do those atoms mass to? Convert this number to grams.

What is the volume of a cube which is 314.1 pm on an edge? Convert to cm³.

Divide mass by volume.

]]> By: ? ?Miss Fame ? ? http://molybdenuminfo.com/2008/08/12/how-do-you-calculate-the-density-of-a-body-centered-unit-cell/#comment-55 ? ?Miss Fame ? ? Fri, 15 Aug 2008 19:48:00 +0000 http://molybdenuminfo.com/?p=68#comment-55 Look here.. Look here..

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