A. the wax is a both; 1. physical change-solid to liquid.
2. chemical change- burned to CO2 + H20 + heat + carbon as seen as black on the rod
b. the wick is neither; the wick does not change, just provides conduit for wax to flame
c. the glass rod is physical change; the carbon is only deported
HOPE THIS HELPS, IVE ALSO LEARNING BEEN LEARNING THIS RECENTLY
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
Formula units in 450 g of
is 1.93 × 10²⁴ formula units.
<u>Explanation:</u>
First we have to find the number of moles in the given mass by dividing the mass by its molar mass as,

Now, we have to multiply the number of moles of Na₂SO₄ by the Avogadro's number, 6.022 × 10²³ formula units/mol, so we will get the number of formula units present in the given mass of the compound.
3.2 mol × 6.022 × 10²³ = 1.93 × 10²⁴ formula units.
So, 1.93 × 10²⁴ formula units is present in 450g of Na₂SO₄.
ANSWER: C) Law of Conservation of Mass
EXPLANATION: In the given cycle, it is seen that th sediments are layered and gets compressed into sedimentary rocks which eventually gets heated and compressed to form metamorphic rocks. But, the total amount of minerals present in the sediments remains the same throughout any stage of the cycle.
This proves the law of conservation of mass which states that mass can not be created nor be destroyed, it can only be transferred from one form to another. So, in this case, only phase transition occurred but the component which is mineral inside the sediments remains constant.
Therefore, the answer is law of conservation of mass.