aluminum is a face centered solidIf each atom has a radius of 1.43 , what is the length of a side of the unit cell, and what is the density of the metal?I would like to know how to solve for this type of problem, not just the answer please
I'm not really sure but I've always wanted to try Nigella Lawsons recipeAll I remember she quickly she cooked the chicken in milk first, which I assume cooked it through firstWhen I tried to make crumbef chicken it didn't cook through.
Egg wash and a flour mixture with flour, Cayenne or red pepper, garlic, onion powder and other yummy spices, make sure to repeat the was and flour step a few times,
This is a spatial problemYou have to picture the atoms in the crystalPicture them as round ballsNow you have to cut out a unit cellAn atom in the middle of the cell will not be cutAn atom on the plane of one face of the cube will be sliced in halfAn atom at one of the eight corners (vertexes vertices) will be cut into 1/8th of a ball - a quarter of a hemisphereYou might try drawing thisthe rest of each of these cut atoms are in adjacent unit cellsSince a corner is shared with 7 other (four on top four on bottom) unit cells only 1/8th of the atom is left in that unit cellFinally you add up all the pieces to get a total number of atomsMultiply that my atomic weight to give you the weight of a Mole of these suckersDivide that by Avogadros number to give you the actual weight of just that unit cellSo now you have the cells weight To figure the size of the cell can be a little trickierYou first have to figure out which atoms are touchingIf the unit cell was like O°O (sorry - lousy sketch) then its possible that the ° is loose in between the big O's - maybe its not touching them so it would be the O-O distance that defines the length of the unit cellIf you Google Face Centered Cubic Unit Cell There will be some images which might help you determine which atoms are touchingIn the olden days I had to build up the crystal structure layer by layer in a sketchBut to do that, you have to be able to see how the FCC structure is embedded in the 3 or 4 layersNo so easyWell the Google images show that on one face a ball in one corner is touching the ball in the middle of the face which is touching the ball at the diagonal vertexThat means that the diagonal distance is 1.43 + 2.86 + 1.43 , so since the two sides are equal, simple trigonometry gives you a dd/√2Each side of cube is a long so all you have to do is convert to centimeters (or cubic cm)And density is weight per volume and you're done.
