Hi, I have the answer for this question, but I can't seem to solve it. I know its simple algebra but just can't get to the right answer. Can someone help me. (College Student)
Q: The unit cell of crystalline iron is body-centered cubic, and the atomic radius of iron is 124.1pm. Determine the length of a unit cell of iron.
A: 286.6pm
2006-12-08 23:47:10 · 5 answers · asked by AUNIDLY 1 in Science & Mathematics ➔ Chemistry
@ aaron, its the asnwer from the back of the book, I just can't seem to get that answer and ned someone to help me on how to get that.
2006-12-08 23:59:41 · update #1
Because body centered cubic means that each of the 8 corners of the cube are touching another, there are 2 atoms per unit cell.
This means that if you take the diagonal of the cube(the body diagonal) it will be equal to twice the radius so body diagonal=2r
using the Pythagorean theorem, you can convert this diagonal to the side of a unit cell with
(4r) = 3s where s is the side of the unit cell
take the square root of both sides
4r = √(3s)
solve for s and substitute your given radius
s= 4r/(√3) = [4(124.1pm)]/(√3) = 286.60pm
2006-12-09 00:14:32 · answer #1 · answered by rm 3 · 2⤊ 0⤋
Hey dude, This is the formula for the unit cell edge length of a Body centred Cubic
a = 4R/sqrt3
a= edge length
R= atomic radius
sqrt= square root
And just in case you need it later for Face Centred Cubics its:
a = 2Rsqrt2
2006-12-09 00:16:13 · answer #2 · answered by Maverick off Top Gun 3 · 0⤊ 0⤋
you have g/cm³ and you like g/mol. From its crystal residences, you will get atoms/ų. in case you recognize atoms/mol and Å/cm, you're able to do the conversion. (Bcc has 2 atoms/unit cellular)
2016-12-30 04:29:19 · answer #3 · answered by ? 4 · 0⤊ 0⤋
Do you?
Try circling a cube!
Begin with circling a square.
OK.Squaring a circle is passe.
2006-12-09 00:09:19 · answer #4 · answered by debussyyee 3 · 0⤊ 0⤋
dude youve got the answer
2006-12-08 23:54:33 · answer #5 · answered by whiteboy 2 · 0⤊ 0⤋