Answer: 
Explanation:
For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here iron is having an oxidation state of +3 called as
cation and oxide
is an anion with oxidation state of -2. Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral
.
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

A.) AlO is the correct formula
I think one is Hydrochloric acid
Really? Really!?
IT'S SCIENCE!
Answer: 1. The empirical formula is
2. The molecular formula is 
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of P = 37.32 g
Mass of N = 16.88 g
Mass of F = 45.79 g
Step 1 : convert given masses into moles.
Moles of P =
Moles of N =
Moles of F =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For P = 
For N = 
For F =
The ratio of P: N: F= 1: 1: 2
Hence the empirical formula is 
The empirical weight of
= 1(31)+1(14)+2(19)= 82.98 g.
The molecular weight = 82.98 g/mole
Now we have to calculate the molecular formula.

The molecular formula will be=