Answer:
Density of unit cell ( rhodium) = 12.279 g/cm³
Explanation:
Given that:
The radius (r) of a rhodium atom = 135 pm
The atomic mass of rhodium = 102.90 amu
For a face-centered cubic unit cell,

where;
a = edge length.
Making "a" the subject of the formula:


a = 381.8 pm
to cm, we get:
a = 381.8 × 10⁻¹⁰ cm
However, recall that:
where;
mass of unit cell = mass of atom × numbers of atoms per unit cell
Also;


Recall also that number of atoms in a unit cell for a face-centered cubic = 4
So;

mass of unit cell = 6.83380375 × 10⁻²² g

Density of unit cell ( rhodium) = 12.279 g/cm³
The increase in the average kinetic energy of the molecules needs the increase of temperature. The relation of ℃ and K is n ℃ = m K -273. So if we change all the K unit to ℃ unit, we can get the answer is (1).
Answer
B I’m pretty sure
Explanation
The gram formula mass of Na2SO4 is 23*2+32+16*4=142. And the mass for sodium is 23*2=46. So the percent by mass is 46/142*100%=32.4%.