Answer:
See explanation below
Explanation:
In this reaction we have the ethyl acetoacetate which is reacting with 2 eq of sodium etoxide. The sodium etoxide is a base and it usually behaves as a nucleophyle of many reactions. Therefore, it will atract all the acidics protons in a molecule.
In the case of the ethyl acetoacetate, the protons that are in the methylene group (CH3 - CO - CH2 - COOCH2CH3) are the more acidic protons, therefore the etoxide will substract these protons instead of the protons of the methyl groups. This is because those hydrogens (in the methylene group) are between two carbonile groups, which make them more available and acidic for any reaction. As we have 2 equivalents of etoxide, means that it will substract both of the hydrogen atoms there, and then, reacts with the Br - CH2CH2 - Br and form a product of an aldolic condensation.
The mechanism of this reaction to reach X is shown in the attached picture.
The number of atoms N = 5.8 x 10²¹
<h3>Further explanation</h3>
A mole is a unit of many particles (atoms, molecules, ions) where 1 mole is the number of particles contained in a substance that is the same amount as many atoms in 12 gr C-12
1 mole = 6.02.10²³ particles
mass of N in 0.82 g of NaNO₃ (MW NaNO₃: 85 g/mol) :

moles of N :

The number of atoms N :

The answer is a. The arteries are red and transfer blood to the heart. Veins are blue and transfer blood away from the heart and to all of the different parts of the body. The capillaries are in-between the veins and arteries and provide blood to cells.
The number of hours required : 37.2 hours
<h3>Further explanation</h3>
Given
⁴²K (potassium -42)
Required
The number of hours
Solution
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually, radioactive elements have an unstable atomic nucleus.
Based on Table N(attached), the half-life for ⁴²K is 12.4 hours, which means half of a sample of ⁴²K will decay in 12.4 hours
For three half-life periods :

1. B, helium
2. B, carbs-lipids-nucleic acids-proteins
hope I helped