Answer : The molal freezing point depression constant of X is 
Explanation : Given,
Mass of urea (solute) = 5.90 g
Mass of X liquid (solvent) = 450.0 g
Molar mass of urea = 60 g/mole
Formula used :

where,
= change in freezing point
= freezing point of solution = 
= freezing point of liquid X= 
i = Van't Hoff factor = 1 (for non-electrolyte)
= molal freezing point depression constant of X = ?
m = molality
Now put all the given values in this formula, we get
![[0.4-(-0.5)]^oC=1\times k_f\times \frac{5.90g\times 1000}{60g/mol\times 450.0g}](https://tex.z-dn.net/?f=%5B0.4-%28-0.5%29%5D%5EoC%3D1%5Ctimes%20k_f%5Ctimes%20%5Cfrac%7B5.90g%5Ctimes%201000%7D%7B60g%2Fmol%5Ctimes%20450.0g%7D)

Therefore, the molal freezing point depression constant of X is 
Two sublevels of the same principal energy level differ from each other through shape and size.
There are mainly 4 energy level s, p, d and f.
The s level has one orbital and one orbital have two electrons. So the maximum number of electron in s sublevel is 2.
The p level has three orbital and one orbital have two electrons. So the maximum number of electron in s sublevel is 6.
The d level has five orbital and one orbital have two electrons. So the maximum number of electron in s sublevel is 10.
The f level has 7 orbital and one orbital have two electrons. So the maximum number of electron in s sublevel is 14.
They may be differ in magnetic level.
Thus, we concluded that Two sublevels of the same principal energy level differ from each other through shape and size.
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Answer:
The constant density decreases
Explanation:
As the temperature of a solvent increases, the solubility of any gas dissolved in that solvent decreases.
For example:
when the temperature of a river, lake or stream is raised high , due to discharge of hot water from some industrial process the solubility of the oxygen in the water is decreased .The fish and the other organisms that live in the water bodies such as rivers, ponds, lakes etc can survive only in the presence of oxygen and decrease in the concentration of the water due to increased temperature can lead to the death of the fish and this may in turn damage the ecosystem.
In the above example, water is considered as the solvent and the oxygen is considered as the solute. When the temperature of the solvent that is water increases, the solubility of the gas that is oxygen in the solvent decreases.
Therefore the answer is decreases
Bohr's atomic model proposed that electrons move in specific orbits around the nucleus of an atom.
Carbon carbon triple bonds