Chemical because the propane has stored chemical energy which is being released and a by-product of that propane is heat or themal energy.
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
Answer:
1.047 M
Explanation:
The given reaction:

For dichromate :
Molarity = 0.254 M
Volume = 15.8 mL
The conversion of mL to L is shown below:
1 mL = 10⁻³ L
Thus, volume = 15.8 ×10⁻³ L
Thus, moles of dichromate :

Moles of dichromate = 0.0040132 moles
1 mole of dichromate react with 6 moles of iron(II) solution
Thus,
0.0040132 moles of dichromate react with 6 × 0.0040132 moles of iron(II) solution
Moles of iron(II) solution = 0.02408 moles
Volume = 23 mL = 0.023 L
Considering:

<u>Molarity = 0.02408 / 0.023 = 1.047 M</u>
1:2:6? Ba(NO3)2 +Na2SO4 -----> BaSO4 + 2NaNO3
Ba(NO3)2
BaSO4
NaNO 3
Na2SO4