Determining the density of Silicon

Thread starter weston_sagle
Start date Oct 13, 2009
Tags

Density Silicon

AI Thread Summary

The density of silicon can be calculated using its unit cell structure, which contains 8 atoms. Given the atomic weight of silicon is 28.09 and the lattice constant is 5.43 angstroms, the conversion of the lattice constant to centimeters is essential. The density formula results in 8 atoms per cubic centimeter, calculated as 8 divided by the volume of the unit cell in cubic centimeters. This yields a density of approximately 4.99 x 10^22 atoms/cm^3. The calculation demonstrates the straightforward relationship between atomic structure and density in silicon.

Oct 13, 2009

weston_sagle

Homework Statement

There are 8 atoms in a unit cell of Si. Silicon has an atomic weight of 28.09 and a lattice constant equal to 5.43 A. Determine the density of silicon/

Homework Equations

The Attempt at a Solution

Physics news on Phys.org

Oct 13, 2009

weston_sagle

Figured it out.
5.43 is in angstroms, which is 10^-8 cm.
So density is atoms for cm^3

so 8/(5.43x10^-8)^3 = 4.99x10^22/cm^3

Simple as that.

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...

View full post »

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...

View full post »

Thread 'Explain this asphalt sheen'

This problem is two parts. The first is to determine what effects are being provided by each of the elements - 1) the window panes; 2) the asphalt surface. My answer to that is The second part of the problem is exactly why you get this affect. And one more spoiler:

View full post »