Explanation:
Atomic number of magnesium is 12 and its electronic distribution is 2, 8, 2. To attain noble gas configuration it is necessary for the magnesium atom to lose two valence electrons and therefore, it forms 
ions.
On the other hand, atomic number of oxygen atom is 8 and its electronic distribution is 2, 6. To attain noble gas configuration it needs to gain two electrons. And, on gaining the electrons it forms 
ions.
Hence, when both magnesium and oxygen ions chemically combine with each other then it forms the compound magnesium oxide (
).
This is because magnesium transfer its two valence electrons to the oxygen atom and due to the formation of opposite charges on these atoms they get attracted towards each other.
PV=nRT will give you the answer I think. I haven’t worked with a certain unit in that problem
Answer: 0.0257 moles of 
and 0.0257 moles of 
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
moles of 
The balanced reaction for dissociation will be:
According to stoichiometry:
1 mole of 
gives 1 mole of and 1 mole of
Thus there will be 0.0257 moles of and 0.0257 moles of
739 is the number of atoms of O in 92.3 moles of Cr3(PO4)2.
Explanation:
Molecular formula given is = Cr3(PO4)2
number of moles of the compound is 92.3 moles
number of 0 atoms in 92.3 moles =?
From the chemical formula 1 mole of the compound has 8 atoms of oxygen
So, it can be written as
1 mole Cr3(PO4)2 has 8 atoms of oxygen
92.3 moles of Cr3(PO4)2 has x atoms of oxygen
= 
x = 8 x 92.3
x = 738.4 atoms
There will be 739 oxygen atoms in the 92.3 moles of Cr3(PO4)2.
-19.15 degrees Celsius. 254k-273.15=-19.15
You have to subtract 273
