Wednesday

September 17, 2014

September 17, 2014

Posted by **Angie** on Saturday, November 14, 2009 at 11:50am.

- AP Chemistry -
**DrBob222**, Saturday, November 14, 2009 at 2:30pmbcc means 2 atoms per unit cell.

mass of unit cell is

2*55.847/6.022 x 10^23 = ?? g/unit cell.

mass = volume x density or

volume = mass/density = ??g/7.86 g/cc = xx cc

a (the edge length) = volume^{1/3}

for a bcc crystal, radius = (a/4)*3^{1/2}. Check my thinking. I obtained 2.87 x 10^-8 cm for the radius. Check my arithmetic and algebra.

- AP Chemistry -
**DrBob222**, Saturday, November 14, 2009 at 2:42pmFor the volume occupied, find the volume of the atoms (4/3)*pi*r^3 (you know r from the first calculation to be 1.24 x 10^-8 cm). Multiply that volume by 2 (because there are 2 atoms/unit cell), then divide by the volume of the unit cell (which I found to be 2.36 x 10^-23 cc) which gives 67.7% which rounds to 68% of the space actually occupied by the atoms. The other 32% is space.

- AP Chemistry--correction -
**DrBob222**, Saturday, November 14, 2009 at 2:52pmI quoted radius above that obtained 2.86 x 10^-8 but that isn't what I found. I found radius of the iron atom to be 1.24 x 10^-8 cm.

**Answer this Question**

**Related Questions**

AP Chemistry - iron has a density of 7.86 g/cm3 and crystallizes a body centered...

chemistry - Vanadium crystalizes in a body centered cubic lattice (the V atoms ...

Chemistry - CdO is cubic with a lattice constant a=4.695 A˚ and a density...

Chemistry - CdO is cubic with a lattice constant a=4.695 A˚ and a density...

chem - Complete the table below: Answer the following for a body centered unit ...

Chemistry - The unit cell with all sides the same length and all angles equal to...

Chemistry - Rank the crystal lattice structures in order of decreasing ...

chemistry - This problem is from my chemistry book and I am having a little ...

Chemistry - crystal structure of cesium chloride (CsCl). 1)Identify the crystal ...

college chem - europium crystallizes in a body-centered cubic cell (the Eu atoms...