This problem is providing the ratio of nitrogen to oxygen by mass in nitrogen monoxide, NO, as 7.0:8.0 and asks for the same ratio but in NO₂ and N₂O₇. After doing the calculations, the results are 7.0:16.0 and 1.0:4.0 respectively.
<h3>Mass ratios:</h3>
In chemistry, one can calculate the mass ratios in chemical formulas according to the atomic mass of each atom. In such a way, one knows the mass ratio of nitrogen to oxygen in NO is 7.0:8.0 because we divide the atomic mass of nitrogen by oxygens:

Now, for chemical formulas with subscripts, one must multiply the atomic mass of the element by the subscript in the formula, which is the case of NO₂ and N₂O₇ as shown below:

Therefore, the results for NO₂ and N₂O₇ are 7.0:16.0 and 1.0:4.0 respectively
Learn more about atomic masses: brainly.com/question/5566317
It take more energy to break the bonds of the reactants and less energy is given off when the product bonds are formed.
<h3>What is Energy?</h3>
Energy is defined as the ability to do work. Work is done in the breaking or formation of bonds.
The standard Enthalpy (ΔH) of water which was formed in the given reaction is negative.
ΔH= Δproduct - Δreactant
This means that the energy to break the bonds of the reactants is more.
Read more about Enthalpy here brainly.com/question/14291557
The correct answer should be B.
The correct answer would be B.
2 is right am 70 percent sure