A formation equation shows how 2 or more elements or compounds react and form another new compound. Some compounds are formed from combining metals and non-metals, from both non-metals, etc.
The element is P (Phosphorus) and the atomic number is just the number of protons so for A it would be 15.
For B to find the atomic mass you would just have to add the protons and neutrons so 15+16=31 and as we can see Phosphorus does have a mass of 31 so for B it would be 31
For C it would be 5
And for D it would be the atomic mass of Phosphorus which is 31 over the atomic number which is 15 so it would be P31/15
<span>0.504 moles
First look up the atomic weight of mercury.
atomic weight of mercury = 200.59
Then divide the mass of the mercury you have by it's atomic weight
101 / 200.59 = 0.503515
So you have 0.503515 moles of mercury. Round the result to 3 significant digits giving you 0.504 moles.</span>
The density of a substance is its mass per unit volume, given by the mass divided by the volume. Density depends on the substance of concern and doesn't matter whether one has a little amount of it or a whole full of it. Therefore, the density of the two smaller pieces is now the same as the original density.