Answer:
518 mL
Explanation:
We can solve this using Boyle's Law Formula
P1V1 = P2V2
where p1 = initial pressure, p2 = final pressure, v1 = initial volume and v2 = final volume
here , the initial pressure is 1 atm and the initial volume is 725mL
we are given the final pressure 1.4 and we need to find the final volume
so we have p1v1 = p2v2
==> plug in p1 = 1 , v1 = 725 mL and p2 = 1.4
(1)(725) = (1.4)v2
==> multiply 1 and 725
725 = (1.4)(v2)
==> divide both sides by 1.4
v2 = 518
N2 would have a volume of 518mL at 1.4atm
Each isotope of Oxygen has a different number of neutrons
<h3>Further explanation
</h3>
The elements in nature have several types of isotopes
Atomic mass is the average atomic mass of all its isotopes
Isotopes are atoms has the same number of protons but has a different number of neutrons.
So Isotopes are elements that have the same Atomic Number (Proton)
Some of the isotopes of oxygen are:

Each isotope has 8 protons and 8 electrons but has a different number of neutrons
For O-16: number of neutrons = 16-8 = 8
For O-17: number of neutrons = 17-8 = 9
For O-18: number of neutrons = 18-8 = 10
Remember: energy is conserved in a chemical reaction (visualize the reaction and question whether heat lies on reactant side (left) or product side (right))
-exothermic- heat is released (heat is on the product side)
>forming an ionic lattice (SALT)- mixture of Na and Cl results in a more stable ionic lattice, causing this reaction to be exothermic
>burning wood
-endothermic- heat is absorbed (heat is on the reactant side)
> cooking an egg