Blog Post 2: Unit Cell of NaCl

Post the height, width and length of the unit cell in nm, angstroms, and meters. (I'm assuming by "unit cell" you mean one molecule of NaCl)

Using a scale of reference we can determine that the actual length, height and width of an NaCl atom. (Withholding the errors in the scale model of course)

The radius of the Na atom is .095nm which is equivalent to 1cm in our model. Using this correlation we can compute the length of one side of the molecule using dimensional analysis. 

(1cm/.095nm)=(3.5cm/xnm)

x=.3325nm

In other units:

x=.332500nm = 3.32500 angstroms = 3.32500*10^10 meters

Since the figure we are trying to compute is relatively square the length used for one side is also equal to the height, width and length

 

Determine and post the mass of one cube of NaCl. Calculate and post the number of moles of NaCl in one cube. Calculate and post the number of NaCl molecules in one cube of salt.

The mass of our cube of NaCl was 4.65e-5 grams. Since the formula for sodium chloride is NaCl we can just add together both AMUs to find the atomic mass

22.98amu + 34.45amu = 57.43amu

Using simple dimensional analysis the number of moles in the sample is: 8.09e-7 mol

Further dimensional analysis of 8.09e-7 mols can reveal how many molecules are in this edible rock.

8.09e-7 mol*(6.022e molecules/ 1mol)=3.667398e17 molecules

Determine the dimension of one cube of salt. Based on the dimensions determined by the unit cell model, determine and post the number of NaCl in one cube of salt.

By our estimations one cube of salt had a side length of .0611mm 61,100 nanometers. Using the fact that one side of a NaCl molecule is .332500nm we can find out how many molecules are in the cube

by using the sublime calculations of dimensional analysis.

(611,000nm)*(1molecule/.3325nm)=1830000 molecules in that length. Of course that is one side but since it's a cube the volume shouldn't be hard to find

V = L*W*H = (1830000molecules)^3

V=6.20^18 molecules in that particular cube of salt.

The answers for two and three aren't consistent. Perhaps the salt molecules aren't as packed edge to edge so when we determine the volume it seems like there are more molecules.