Answer:
Mg₃N₂
Explanation:
The empirical formula of a chemical compound is defined as the simplest positive integer ratio of atoms present in a compound. Using molecular mass of Mg (24,305g/mol) and mass of nitrogen (14,006g/mol), moles of each element are:
0,73g × (1mol / 24,305g) = 0,03 moles of Mg
0,28g × (1mol / 14,006g) = 0,02 moles of N
Dividing each value in 0,01 to obtain natural numbers:
0,03 moles of Mg / 0,01 = 3
0,02 moles of N / 0,01 = 2.
Thus, empirical formula is: <em>Mg₃N₂</em>
<em></em>
I hope it helps!
answer : Neutron, neutral subatomic particle that is a constituent of every atomic nucleus except ordinary hydrogen.
The chemical formula of oxalic is 
When oxalic acid reacts with water, first, oxalic acid removes one proton and results in the formation of mono acids.
After that, in second step, oxalic acid in aqueous solution removes another proton which shows it is a polyprotic acid.
The chemical equations are: (the reactions occurs in two steps due to presence to hydrogen atoms).
When one proton is removed:

When another proton is removed:

The dissociation of oxalic acid in water in shown in the image.
This is a combined gas law problem, according to which

where P is the pressure of the gas, V is the volume of the gas, and T is the temperature of the gas, and the subscripts 1 and 2 correspond to the initial and final conditions of the gas. In this problem, we are given the initial pressure, volume, and temperature of the gas in the balloon:
P₁ = 1.0 atm
V₁ = 1.8 L
T₁ = 295.15 K (K = °C + 273.15).
Moreover, we are given the final pressure and temperature of the gas in the balloon.
P₂ = 0.86 atm
T₂ = 281.15 K.
What we want to find is the final volume, V₂, which we can obtain by rearranging the combined gas equation to solve for V₂:

This answer has three significant figures. However, the question as written would warrant an answer that comprises one significant figure (as 8 °C has only one sig fig). In that case, the answer would be 2 L. If the answer is to be given to two significant figures, the volume would then be 2.0 L.