C. Distance from Earth
The observed brightness of a star (the apparent magnitude) to an absolute magnitude, you need to know the distance [d], to the star. Alternatively, if we know the distance and the apparent magnitude [m] of a star, we can calculate its absolute magnitude [d].
*paraphrased from "COSMOS.com"
The astronomical unit or also know as AU. Scientists use this because it’s convenient and easier to understand! Hope this helps ;)
Answer:
Y is a 3-chloro-3-methylpentane.
The structure is shown in the figure attached.
Explanation:
The radical chlorination of 3-methylpentane can lead to a tertiary substituted carbon (Y) and to a secondary one (X).
The E2 elimination mechanism, as shown in the figure, will happen with a simulyaneous attack from the base and elimination of the chlorine. This means that primary and secondary substracts undergo the E2 mechanism faster than tertiary substracts.
Answer:
SeCl₆ < SeF₂ < SeO₂
Explanation:
(A) SeO₂
The central atom has 2 bond pairs and 1 lone pair. The molecule is bent shaped which has an angle of 120°.
(B) SeCl₆
The central atom has 6 bond pairs and 0 lone pair. The geometry is octahedral in which the equatorial bonds has an angle of 90° and axial bond has an angle of 90°.
(C) SeF₂
The central atom has 2 bond pairs and 2 lone pairs. The geometry is bent shape which has an angle of approximately 105.5°.
The order is:
<u>SeCl₆ < SeF₂ < SeO₂</u>
