We have to know the number of Na⁺ ions in the unit cell.
The number of Na⁺ ions in the unit cell is (D) 8.
Sodium oxide (Na2O) crystallizes in a structure in which the O2– ions are in a face - centered cubic lattice and the Na+ ions are in tetrahedral holes.
O²⁻ ions are in a face centred cubic lattice, so the number of O²⁻ ions per unit cell is equal to 4. The number of tetrahedral hole= 2 X 4=8. Na+ ions are present in tetrahedral holes, which indicates there are 8 number of Na+ ions in the unit cell.
Answer:
Explanation:
Percent composition is percentage by the mass of element present in the compound.
The formula for chromium(III) nitrate is 
Molar mass of chromium(III) nitrate = 238.011 g/mol
1 mole of chromium(III) nitrate contains 9 moles of oxygen
Molar mass of oxygen = 16 g/mol
So, Mass= Molar mass*Moles = 16*9 g = 144 g
a) The least number of decimal points is 0 so you should round the answer to 43.
b) The least number of significant figures is 2 so round to 7.3
c)The least number of decimal places is 1 so round to 225.7
d) The least number of significant figures is 3 so round to 92.0
e) The least number of significant figures is 3 so round to 32.4
f) The least number of decimal places is 0 so round to 104m^3
Basically, for addition and subtraction round to the least number of decimal places found in the factors, and for multiplication and division round to the least number of significant figures found in the factors.
Answer:
8 Silicon atom are present in unit cell.
16 oxygen atoms are present unit cell.
Explanation:
Number of atoms in unit cell = Z =?
Density of silica = tex]2.32 g/cm^3[/tex]
Edge length of cubic unit cell = a = 0.700 nm = 

Molar mass of Silica = 
Formula used :
where,
= density
Z = number of atom in unit cell
M = atomic mass
= Avogadro's number
a = edge length of unit cell
On substituting all the given values , we will get the value of 'a'.
1 silicon is 2 oxygen atoms. then 8 silicon atoms will be 16 oxygen atoms.
Hello!
To solve this question, we need to use the
Avogadro's Number, which is a constant first discovered by
Amadeo Avogadro, an Italian scientist. He discovered that in a mole of a substance, there are
6,02*10²³ molecules. Using this relationship, we apply the following conversion factor:

So, 8,50 * 10²⁴ molecules of Na₂SO₃ represent
14,12 moles of Na₂SO₃
Have a nice day!