The time take by Neptune to travel once around the Sun is called the orbital period. It takes Neptune about 165 Earth years to make one complete orbit around the Sun.
I think it might be D or B
And my other two might be A or C
Empirical formula is the simplest ratio of components making up the compound. the molecular formula is the actual ratio of components making up the compound.
the empirical formula is CH₂. We can find the mass of CH₂ one empirical unit and have to then find the number of empirical units in the molecular formula.
Mass of one empirical unit - CH₂ - 12 g/mol x 1 + 1 g/mol x 2 = 12 = 14 g
Molar mass of the compound is - 252 .5 g/mol
number of empirical units = molar mass / mass of empirical unit
= 
= 18 units
Therefore molecular formula is - 18 times the empirical formula
molecular formula - CH₂ x 18 = C₁₈H₃₆
molecular formula is C₁₈H₃₆
Answer: Option A. 6.022 x 10^23
Explanation:
5. Eubacteria
6. Plantae
7. Animalia
8. Protist (technically not a kingdom)
9. Archaebacteria
10. Fungi